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SUMMARY TECHNICAL REPORT 
OF THE 

NATIONAL DEFENSE RESEARCH COMMITTEE 


This document contains information affecting the national 
defense of the United States within the meaning of the 
Espionage Act, 50 U. S. C., 31 and 32, as amended. Its trans- 
mission or the revelation of its contents in any manner to an 
unauthorized person is prohibited by law. 

This volume is classified CONFIDENTIAL in accordance 
with security regulations of the War and Navy Departments 
because certain chapters contain material which was CON- 
FIDENTIAL at the date of printing. Other chapters may 
have had a lower classification or none. The reader is advised 
to consult the War and Navy agencies listed on the reverse 
of this page for the current classification of any material. 


Manuscript and illustrations for this volume were prepared 
for publication by the Summary Reports Group of the Co- 
lumbia University Division of War Research under contract 
OEMsr-1131 with the Office of Scientific Research and De- 
velopment. This volume was printed and bound by the 
Columbia University Press. 

Distribution of the Summary Technical Report of NDRC 
has been made by the War and Navy Departments. Inquiries 
concerning the availability and distribution of the Summary 
Technical Report volumes and microfilmed and other refer- 
ence material should be addressed to the War Department 
Library, Room lA-522, The Pentagon, Washington 25, 
D. C., or to the Office of Naval Research, Navy Department, 
Attention: Reports and Documents Section, Washington 
25, D. C. 


Copy No. 

70 


This volume, like the seventy others of the Summary Tech- 
nical Report of NDRC, has been written, edited, and printed 
under great pressure. Inevitably there are errors which 
have slipped past Division readers and proofreaders. There 
may be errors of fact not known at time of printing. The 
author has not been able to follow through his writing to 
the final page proof. 


Please report errors to : 

JOINT RESEARCH AND DEVELOPMENT BOARD 
PROGRAMS DIVISION (STR ERRATA) 

WASHINGTON 25, D. C. 

A master errata sheet will be compiled from these reports 
and sent to recipients of the volume. Your help will make 
this book more useful to other readers and will be of great 
value in preparing any revisions. 


SUMMARY TECHNICAL REPORT OF DIVISION 6, NDRC 


VOLUME 1 I 


A MANUAL OF 

CALIBRATION MEASUREMENTS 
OF SONAR EOUIPMENT 


OFFICE OF SCIENTIFIC RESEARCH AND DEVELOPMENT 
VANNEVAR BUSH, DIRECTOR 

NATIONAL DEFENSE RESEARCH COMMITTEE 
JAMES B. CON ANT, CHAIRMAN 

DIVISION 6 
JOHN T. TATE, CHIEF 


WASHINGTON, D. C., 1946 


NATIONAL DEFENSE RESEARCH COMMITTEE 


James B. Conant, Chairman 
Richard C. Tolman, Vice Chairman 
Roger Adams Army Representative^ 

Frank B. Jewett Navy Representative- 

Karl T. Compton Commissioner of Patents^ 

Irvin Stewart, Executive Secretary 


'^Army representatives in 07'der of service: 


^Navy representatives in order of service: 


Maj. Gen. G. V. Strong 
Maj. Gen. R. C. Moore 
Maj. Gen. C. C. Williams 
Brig. Gen. W. A. Wood, Jr. 


Col. L. A. Denson 
Col. P. R. Faymonville 
Brig. Gen. E. A. Regnier 
Col. M. M. Irvine 


Col. E. A. Routheau 


Rear Adm. H. G. Bowen Rear Adm. J. A. Furer 
Capt. Lybrand P. Smith Rear Adm. A. H. Van Keuren 
Commodore H. A. Schade 
^Commissioners of Patents in order of service : 
Conway P. Coe Casper W. Ooms 


NOTES ON THE ORGANIZATION OF NDRC 


The duties of the National Defense Research Committee 
were (1) to recommend to the Director of OSRD suitable 
projects and research programs on the instrumentalities 
of warfare, together with contract facilities for carry- 
ing out these projects and programs, and (2) to admin- 
ister the technical and scientific work of the contracts. 
More specifically, NDRC functioned by initiating re- 
search projects on requests from the Army or the Navy, 
or on requests from an allied government transmitted 
through the Liaison Office of OSRD, or on its own con- 
sidered initiative as a result of the experience of its 
members. Proposals prepared by the Division, Panel, or 
Committee for research contracts for performance of the 
work involved in such projects were first reviewed by 
NDRC, and if approved, recommended to the Director of 
OSRD. Upon approval of a proposal by the Director, a 
contract permitting maximum flexibility of scientific 
effort was arranged. The business aspects of the con- 
tract, including such matters as materials, clearances, 
vouchers, patents, priorities, legal matters, and admin- 
istration of patent matters were handled by the Execu- 
tive Secretary of OSRD. 

Originally NDRC administered its work through five 
divisions, each headed by one of the NDRC members. 
These were: 

Division A — Armor and Ordnance 
Division B — Bombs, Fuels, Gases, & Chemical Problems 
Division C — Communication and Transportation 
Division D — Detection, Controls, and Instruments 
Division E — Patents and Inventions 


In a reorganization in the fall of 1942, twenty-three 
administrative divisions, panels, or committees were 
created, each with a chief selected on the basis of his 
outstanding work in the particular field. The NDRC 
members then became a reviewing and advisory group 
to the Director of OSRD. The final organization was as 
follows: 

Division 1 — Ballistic Research 

Division 2 — Effects of Impact and Explosion 

Division 3 — Rocket Ordnance 

Division 4 — Ordnance Accessories 

Division 5 — New Missiles 

Division 6 — Sub-Surface Warfare 

Division 7 — Fire Control 

Division 8 — Explosives 

Division 9 — Chemistry 

Division 10 — Absorbents and Aerosols 

Division 11 — Chemical Engineering 

Division 12 — Transportation 

Division 13 — Electrical Communication 

Division 14 — Radar 

Division 15 — Radio Coordination 

Division 16 — Optics and Camouflage 

Division 17 — Physics 

Division 18 — War Metallurgy 

Division 19 — Miscellaneous 

Applied Mathematics Panel 

Applied Psychology Panel 

Committee on Propagation 

Tropical Deterioration Administrative Committee 


iv 




Library of Congress 



490956 


NDRC FOREWORD 


A s EVENTS of the years preceding 1940 re- 
^ vealed more and more clearly the serious- 
ness of the world situation, many scientists in 
this country came to realize the need of organ- 
izing scientific research for service in a national 
emergency. Recommendations which they made 
to the White House were given careful and sym- 
pathetic attention, and as a result the National 
Defense Research Committee [NDRC] was 
formed by Executive Order of the President in 
the summer of 1940. The members of NDRC, 
appointed by the President, were instructed to 
supplement the work of the Army and the Navy 
in the development of the instrumentalities of 
war. A year later, upon the establishment of the 
Office of Scientific Research and Development 
[OSRD], NDRC became one of its units. 

The Summary Technical Report of NDRC is 
a conscientious effort on the part of NDRC to 
summarize and evaluate its work and to present 
it in a useful and permanent form. It comprises 
some seventy volumes broken into groups cor- 
responding to the NDRC Divisions, Panels, and 
Committees. 

The Summary Technical Report of each Divi- 
sion, Panel, or Committee is an integral survey 
of the work of that group. The first volume of 
each group’s report contains a summary of the 
report, stating the problems presented and the 
philosophy of attacking them, and summarizing 
the results of the research, development, and 
training activities undertaken. Some volumes 
may be “state of the art” treatises covering 
subjects to which various research groups have 
contributed information. Others may contain 
descriptions of devices developed in the labora- 
tories. A master index of all these divisional, 
panel, and committee reports which together 
constitute the Summary Technical Report of 
NDRC is contained in a separate volume, which 
also includes the index of a microfilm record of 
pertinent technical laboratory reports and ref- 
erence material. 

Some of the NDRC-sponsored researches 
which had been declassified by the end of 1945 
were of sufficient popular interest that it was 
found desirable to report them in the form of 
monographs, such as the series on radar by 
Division 14 and the monograph on sampling 
inspection by the Applied Mathematics Panel. 
Since the material treated in them is not du- 


plicated in the Summary Technical Report of 
NDRC, the monographs are an important part 
of the story of these aspects of NDRC research. 

In contrast to the information on radar, 
which is of widespread interest and much of 
which is released to the public, the research on 
subsurface warfare is largely classified and is 
of general interest to a more restricted group. 
As a consequence, the report of Division 6 is 
found almost entirely in its Summary Technical 
Report, which runs to over twenty volumes. 
The extent of the work of a Division cannot 
therefore be judged solely by the number of 
volumes devoted to it in the Summary Technical 
Report of NDRC : account must be taken of 
the monographs and available reports published 
elsewhere. 

Any great cooperative endeavor must stand 
or fall with the will and integrity of the men 
engaged in it. This fact held true for NDRC 
from its inception, and for Division 6 under the 
leadership of Dr. John T. Tate. To Dr. Tate and 
the men who worked with him — some as mem- 
bers of Division 6, some as representatives of 
the Division’s contractors — belongs the sincere 
gratitude of the Nation for a difficult and often 
dangerous job well done. Their efforts contrib- 
uted significantly to the outcome of our naval 
operations during the war and richly deserved 
the warm response they received from the Navy. 
In addition, their contributions to the knowl- 
edge of the ocean and to the art of oceano- 
graphic research will assuredly speed peacetime 
investigations in this field and bring rich bene- 
fits to all mankind. 

The Summary Technical Report of Division 6, 
prepared under the direction of the Division 
Chief and authorized by him for publication, 
not only presents the methods and results of 
widely varied research and development pro- 
grams but is essentially a record of the un- 
stinted loyal cooperation of able men linked in 
a common effort to contribute to the defense 
of their Nation. To them all we extend our 
deep appreciation. 

Vannevar Bush, Director 
Office of Scientific Research and Development 

J. B. CoNANT, Chairman 
National Defense Research Committee 



FOREWORD 


T his report, supplementing Volume 10 on 
calibration methods, presents a compilation 
of data relative to a wide variety of projectors 
and hydrophones. Certain of these units de- 
veloped were for use as standards while others 
were developed as parts of gear intended for 
service use. The agency developing the instru- 
ment or devices is in each case indicated. The 
acoustical and electrical data included are based 
on tests made at the Mountain Lakes, New 
Jersey and Orlando, Florida test stations of the 
Underwater Sound Reference Laboratories 
[USRL] operating under Contract OEMsr-1130 
with Columbia University. This report has 
been prepared by that organization. 

It may be stated that a somewhat less com- 
prehensive compilation was undertaken several 
years ago in the form of the Dictionary of 
Underwater Acoustical Devices issued by 
USRL. The usefulness and wide acceptance of 
the dictionary seems to justify the more 


comprehensive assembling of the material 
In carrying on the work described in this re- 
port the Division and its contractor have had 
the cordial support and counsel of the Office of 
the Coordinator of Research and Development. 
In addition constant and most helpful contact 
has been maintained with the Navy liaison 
officers designated for the various projects. On 
page 352 are listed the principal Navy proj- 
ects under which this particular work was 
performed. 

The Division also wishes to express its ap- 
preciation of the cooperation afforded by a 
number of industrial organizations operating 
under Navy contracts. These have furnished 
models for test and members of their staffs have 
given time freely to the Hydrophone Advisory 
Committee (see page 353). 

John T. Tate 
Chief, Division 6 



vii 





PREFACE 


T his volume summarizes and presents the 
calibrations made by the Underwater Sound 
Reference Laboratories on various sonar equip- 
ment developed by the NDRC, as well as by the 
Navy and its contractors. It includes not only 
those data originally in the USRL Dictionary of 
Underwater Acoustical Devices, but also addi- 
tional information collected during 1944 and 
1945. 

As it is intended that this volume serve pri- 
marily as a reference for those interested in the 
basic performance figures of sonar gear, the 
information has been grouped arbitrarily into 
seven chapters. 

The scientific staffs at the Mountain Lakes 
and Orlando 'stations, together with those of 


other Division 6 and naval laboratories, have 
collaborated in collecting data included in this 
volume and preparing it in suitable form for 
publication. This group includes : Edwin L. 
Carstensen, E. Dietze, W. Richard Elliott, 
Leslie L. Foldy, Frank H. Graham, Earle C. 
Gregg, Jr., Erhard Hartmann, Norma Hart- 
mann, F. William Hoffman, Paul F. Joly, Joseph 
B. Keller, Martin J. Klein, L. Pauline Leighton, 
Lucille Northrop, Henry Primakoff, Edward S. 
Rogers, Robert S. Shankland, Erwin F. 
Shrader, D. Bernard Simmons, Richard J. 
Tillman. 

Robert S. Shankland 
Editor 


ix 




CONTENTS 


CHAPTER PAGE 

1 Standards Used by the Underwater Sound Ref- 
erence Laboratories 1 

2 U. S. Navy Sonar Equipments 50 

3 Domes 160 

4 British and Canadian Equipment . . . . 176 

5 Naval Laboratories’ Designs 194 

6 NDRC Division 6.1 Designs 204 

7 Industrial Designs 275 

Glossary 341 

Bibliography 343 

Contract Numbers 351 

Project Numbers 352 

Hydrophone Advisory Committee .... 353 

Index 355 






Chapter 1 

STANDARDS USED BY THE UNDERWATER SOUND REFERENCE 

LABORATORIES 


INTRODUCTION 

A S POINTED OUT PREVIOUSLY^^ most of the 
^ calibration tests made by the Underwater 
Sound Reference Laboratories [USRL] have 
been the comparison type, in which measure- 
ments relative to a standard are taken. A 
standard can be defined as a device for which 
an absolute calibration is available and which 
is used as a basis of comparison in testing other 
instruments. • 

Before the reciprocity method was estab- 


and moving coil, the flux density in the air 
gaps, and the length of the conductor in the 
coil.^ The predicted performance was checked 
by means of response measurements in air, and 
the calibration in water was then worked out 
from that in air.^ 

Another primary standard used by the USRL 
is the CMF hydrophone (see Section 1.4.18), 
which can be calibrated in absolute terms on a 
quasistatic^ basis. 

A third example is the low-frequency pres- 
sure tank system, which is capable of being 


Comparison of Projector Standards Manufactured by BTL on NDRC Contract for USRL 


Code 

No. 

Type of 
construction 

Frequency 

range 

(kc) 

Maximum 
permissible 
input (w) 

Directivity 
index (db) 

5A 

ADP 

20-150 

0.1 

-13.0 (70 kc) 

2B 

Y-cut Rochelle salt 

7.5-28 

7 

-9.0 (23 kc) 

3B 

Y-cut Rochelle salt 

28-100 

Decreases with 
frequency from 

5 to 0.5 

-8.0 (30 kc) 

4B 

Moving coil 

0.008-0.5 

125 

Nondirective 

6B 

Y-cut Rochelle salt 

10-80 

0.1 

-16.3 (70 kc) 

IK 

Moving coil 

0.1-10 

20 above 400 c 

Nondirective 

MH 

X-cut quartz 

100-2,200 

3 

-19.5 (150 kc) 


lished and applied by the USRL as a means for 
obtaining absolute calibrations, a distinction 
was made between primary standards, which 
were calibrated by absolute means, and sec- 
ondary standards, which were calibrated by 
comparison with the primary standards and 
then in turn used as standards in comparison 
tests. Often the secondary standards had cer- 
tain practical advantages as they were more 
rugged, had a higher output level, could handle 
a larger input, etc. 

The lA pressure gradient hydrophone (see 
Section 1.4.10) is one of the primary standards 
that was used by the USRL. Its response in air 
and water is predictable from its design con- 
stants, that is, the area and mass of the magnet 


calibrated on an absolute basis independent of 
auxiliary hydrophone standards.’' 

With the reciprocity calibration method all 
instruments, provided at least one of them is 
reversible, can be calibrated independently so 
that the difference between primary and sec- 
ondary standards largely disappears. Instru- 
ments can then be selected as standards merely 
on the basis of the suitability of their char- 
acteristics.^ 

One of the most important requirements for 
a standard is dependability, that is, a standard 
should give the same performance day in and 
day out under various conditions of use so that, 

^ See STR Division 6, Volume 10, Chapter 5. 

^ See STR Division 6, Volume 10, Chapter 6. 


1 


2 


USRL STANDARDS 


once its calibration has been determined, it 
can be relied upon for an extensive period of 
time and under a wide range of testing condi- 
tions. This requirement is more easily met in 
hydrophones than in projectors, the latter 
being subject to heating, internal temperature 
stresses, etc., produced by the power dissipated 
in the projector. The problem of dependability 
is mainly one of design, including the material 
of which the instrument is made. The X-cut 
Rochelle salt crystal, because of its tempera- 
ture dependence, for instance, should in gen- 
eral be avoided for standards. Instead, 45° 
Y-cut crystals have been used. A disadvantage 
of the Y-cut crystal is its high electric im- 
pedance, which demands the use of a high input 
impedance preamplifier in order to obtain an 
appreciable fraction of the generated voltage. 
On the other hand, the Y-cut crystal has no 
hysteresis and its constants are practically 
independent of temperature and loading con- 
straint. More recently ADP (ammonium di- 
hydrogen phosphate, NH4H2PO4) crystals have 
come into use and are now replacing the Y-cut 
Rochelle salt crystal. The ADP is cut along the 
Z axis. Its acoustical and electrical character- 
istics are similar to those of Y-cut Rochelle salt, 
but its mechanical characteristics are superior. 
It is stable in air up to 93 per cent humidity 
and its melting temperature point is at 190 C, 
although at 125 C loss of ammonia results. 


12 PROJECTOR STANDARDS 

The majority of the standards used by the 
USRL have been designed by the Bell Tele- 
phone Laboratories [BTL] on NDRC contract 
expressly for calibration purposes, in accord- 
ance with requirements for frequency range, 
output level, directivity, etc., furnished by the 
USRL. The following projector standards have 
been produced on this basis. 

For the low-frequency range, the 4B and IK 
projector standards are used by the USRL. 
These are both electrodynamic units." This type 
unit seems to be particularly well suited for 
the generation of low frequencies. The British 

® See STR Division 6, Volume 10, Chapter 2. 


hydrosounder and a low-frequency source de- 
signed by the Naval Ordnance Laboratory are 
also of this type. 

The efficiency of the 4B and IK units is of 
the order of — 25 to — 30 db vs the ideal, 
whereas crystal projectors have been designed, 
but not for the low frequencies, with only a 
few decibels loss. The low efficiency of the 
dynamic unit is due to the large dissipation in 
the copper and iron. Not only is the efficiency 
low but the amount of power which can be 
applied to the units is limited by overheating. 
At low frequencies another factor limits the 
output, namely, the maximum amplitude of 
motion that the diaphragm can produce. Also 
the static pressure must at all times be equal 
on both sides of the diaphragm. How this pres- 
sure equalization is accomplished is covered 
in the description of the two units. When the 
necessary precautions are taken,^> it is pos- 
sible to use these units at depths up to 50 ft, 
which is as great as any normally required in 
USRL calibrating work. 

At the higher frequencies it is possible to 
use crystal projectors. These are efficient and 
have reasonably uniform response. The useful 
frequency range of any one projector, however, 
is limited by the size of the projector. As the 
frequency is increased, a unit of a given size 
becomes more and more directional until finally 
the beam becomes so sharp that it no longer 
provides a uniform sound field for testing. 
When the projector beam is too sharp, any 
small change in alignment of the testing sys- 
tem causes large changes in sound level at the 
test point. For this reason, among others, the 
6B is used only to 80 kc, and the 5 A projector, 
which is smaller and hence less directional, is 
used above 80 kc. Similar considerations are 
applicable to the MH transducers, which are 
used in the high-frequency system. The crystal 
unit used from 100 to 800 kc has a diameter of 
3 cm, whereas the one used from 300 kc to 2.2 
me has a 1-cm diameter. 

The 2B and 3B projectors consist of an array 
of 45° Y-cut crystal blocks of different sizes, 
each mechanically resonated at its own natural 
frequency by means of a half-wavelength res9- 
nator. This leads to a highly efficient design. 


HYDROPHONE STANDARDS 


3 


These units, however, have not proven too 
satisfactory for the close-up, precision testing 
that comprises most of the work done by the 
USRL. This is because of the phase difference 
between the sound from the different crystals 
and the shift in the origin of the sound field 
position with the change in the contribution 
from the different crystals. For these reasons 
the sound intensity does not obey the inverse 
square law distance relation too well until the 
testing distance becomes so great (at least 
10 m) that the whole unit approximates a point 
source. Therefore, these projectors have been 
used more by other groups in the underwater 
sound field who test at greater distances than 
the USRL. 

In addition to the above, a number of trans- 
ducers made by the Brush Development Com- 
pany of Cleveland, Ohio, have been used as 
sound sources by the USRL, particularly the 
C13 and the AX-70, which have good direc- 
tivity characteristics in the supersonic range 
but which, being made of X-cut Rochelle salt 
crystals, are subject to change with tempera- 
ture. For a projector with this characteristic, 
it is not sufficient that the water temperature 
be constant, because the crystal temperature 
will increase whenever power is applied to it. 
The performance of these units may be fairly 
well controlled by supplying them from a high- 
impedance source. The efficiency of such a sys- 
tem is low, since a large fraction of the supplied 
power is dissipated in the source. It is realized 
that a constant current circuit would minimize 
these troubles to a considerable degree. The 
Brush Development Company has recently pro- 
duced the AX-124 transducer (see Section 
1.4.2). This unit, which is essentially the C13 
with ADP crystals and is free from tempera- 
ture effects, would be considerably more satis- 
factory for use as a sound source. 


HYDROPHONE STANDARDS 

The general requirements for the selection 
of a hydrophone for use as a standard have 
been outlined previously.'^ However, the selec- 
^ See STR Division 6, Volume 10, Chapter 5. 


tion of a standard for a particular test fre- 
quently requires additional consideration. 

1. It is necessary that the standard have a 
reasonably uniform response within the im- 
portant frequency range of the device under 
test. Often, in order to achieve this, a particular 
hydrophone is selected. It is obvious that any 
irregularity in the response of the standard 
renders it more difficult to determine accurately 
response variations in the test instrument in 
the same frequency range. The situation is 
even worse if the sound source also has irregu- 
larities in this range. For instance, some 3A 
hydrophones have irregularities in the 20-kc 
range. By using the OLA hydrophone, which is 
particularly smooth in this range, to supple- 
ment the measurements with the 3A hydro- 
phone, it is possible to improve the accuracy of 
the calibrations. 

2. The output of the hydrophone including 
its preamplifier should be linear with sound 
pressure over the frequency range for the 
range of pressures used in the test. In order to 
meet this requirement in the measurement of 
projectors under full power and in tests on 
underwater sound explosions, it was necessary 
to use a special 3A shunted down with capacity 
at the input so that its preamplifier would not 
overload. Of course, such an instrument has 
also correspondingly lower response. 

3. A hydrophone used as a standard should 
be low in impedance to reduce the tendency for 
electric pickup in the leads, or else a pre- 
amplifier, preferably of the cathode-follower 
type, having a low output impedance should be 
immediately associated with it. The lA and 2A 
hydrophones are illustrations of the first type, 
the 5E and 3A of the latter type. 

4. In order to have a uniform response, the 
hydrophone should not be used near its res- 
onant frequency. This procedure is illustrated 
by the use of the lA and 2A hydrophones, 
which have low-frequency resonances and are 
used well above their natural frequencies, and 
by the 5E and 3A hydrophones, which are 
normally used below their natural frequencies. 

5. The hydrophone standards should be non- 
directive or should have broad beams. It is 
not always possible to use nondirective instru- 


4 


USRL STANDARDS 


ments because of interference. Here the lA and 
2A hydrophones, which are of the pressure 
gradient type and have a directivity pattern 
which follows a cosine function, are of advan- 
tage. In some cases it is more desirable to em- 
ploy more directive projectors, as, for instance, 
the 6B or C13. Units which are too directive, 
however, are undesirable, as they render the 
testing setup quite critical. 

6. In order to be free from electrical inter- 
ference, it is desirable that the hydrophone 


Specific information with respect to these in- 
struments is given in the sections dealing with 
them. 

In addition to the above-mentioned hydro- 
phones, a number of instruments manufac- 
tured by other groups in the underwater sound 
field have been used as standards by the USRL. 
These include the CMF condenser hydrophone, 
which has an absolute calibration on a quasi- 
static basis and is useful for very low fre- 
quencies up to 75 c.® The HK type hydrophone 


Hydrophone Standards Used by USRL Designed by BTL on NDRC Contract 


Code 

No. 

Type of 
construction 

Frequency 
range (kc) 

Threshold 

(db) 

Directivity 
index (db) 

lA 

Moving coil 

0.1-50 

-40 (1 kc) 

Approx, cosine pattern 

2A 

Moving coil 

0.5-100 

-32 (25 kc) 

Approx, cosine pattern 

3A 

ADP 

0.05-150 

-55 (10 kc) 

Nondirective up to 15 kc 

5C 

X-cut Rochelle salt 

0.002-10 

-75 (10 kc) 

-5 (10 kc) 

5E 

Y-cut Rochelle salt 

0.1-40 

-75 (10 kc) 

-5 (10 kc) 

MH 

X-cut quartz 

100-800 


-19.5 (150 kc) 

MH 

X-cut quartz 

300-2,200 


-24.2 (750 kc) 


electric circuit be balanced to ground and that 
the sound head be shielded. The shielding is 
accomplished by enclosing the head in metal 
(see 3 A hydrophones). In cases where this 
shielding is not provided, it can be added by 
painting the head with a conducting (metallic) 
paint. The shield, of course, should be con- 
nected to ground. Shielding of the head is more 
important in fresh water than in sea water, 
which is highly conductive. 

7. When any one of several standards hav- 
ing the same threshold can be used, the one 
with the higher sensitivity will, in general, be 
more satisfactory. High sensitivity avoids the 
necessity for high amplification of the signal, 
permits the use of amplifiers with higher in- 
herent noise levels, and decreases cross-talk 
problems. Of course, when high signal pres- 
sures are to be measured, low sensitivity may 
be necessary to avoid overloading the ampli- 
fier. 

The following table compares the different 
hydrophone standards which were designed 
for the USRL by the BTL on NDRC contract. 


developed by the Massachusetts Institute of 
Technology [MIT] was used for low-frequency 
measurements and has very similar character- 
istics to the 5C hydrophones. The HK unit 
using X-cut Rochelle salt crystals, however, 
does not possess the stability of the types de- 
veloped later. The B19-B and the OLA instru- 
ments have been used at echo-ranging fre- 
quencies. The XMX hydrophone developed by 
MIT is a unit which has proven extremely 
valuable because it covers such an exceedingly 
broad frequency range and therefore is espe- 
cially suited for the measurement of aperiodic 
sound waves, such as explosions and noises. 
The XMX hydrophone, however, has a number 
of disadvantages: (1) It uses X-cut Rochelle 
salt crystals and thus has to be calibrated each 
time it is used. Some experimental work has 
already been done to substitute other crystals. 
(2) For the same reason, it must be connected 
to a very high impedance. Since it is very high 
impedance, even a short length of lead between 


® See STR Division 6, Volume 10, Chapter 5. 



HYDROPHONE STANDARDS 


5 


this unit and the receiving amplifier cannot be 
tolerated. A condenser circuit has been de- 
signed by the USRL which can be directly 
associated with it under water. This circuit 
provides a high-impedance termination for the 
crystal and presents a low impedance to the 


cable. (3) It is insufficiently shielded, which 
has caused electric pickup trouble in some tests. 
This lack of shielding has been overcome by 
painting the head with metallic paint. These 
defects are minor and can readily be overcome, 
as illustrated. 


6 


USRL STANDARDS 


STANDARD INSTRUMENTS 
^ 5A Projector 


Type: ADP Crystal. 

Operating range: 20 to 150 kc. 

Designer: Bell Telephone Laboratories. 

Manufacturer : Western Electric Company. 

Reference: NDRC Report No. 6.1-sr783-1329, February 7, 1945.^® 

Description: Consists of a crystal transducer unit and a transformer in 
a common housing. The transducer unit contains an array of ammonium 
dihydrogen phosphate crystals mounted between the diaphragm, which is 
exposed to the water, and a steel backing plate. It is designed to work from 
a circuit having 135 ohms impedance. The projector, except for the dia- 
phragm end, is encased in a layer of low-impedance sound-reflecting cork 
and rubber material. A 30-ft shielded, flexible, 2-conductor, rubber-covered 
cord is provided for connecting the projector to the sound source. For 
schematic circuit drawing, see Figure 33 in Section 1.4.6. 

Overall diameter: 2% in. 

Overall length: 7 in. 

Weight: 9 lb. 

Recommended maximum power input: 0.1 w from a 135-ohm source. 

Efficiency: Approximately — 18.5 db vs ideal at 70 kc. 



STANDARD INSTRUMENTS 


7 


90° 



180' 


90- 


Figure 1. Directivity patterns, 5 A projector. 



Figure 2. Transmitting response, 5A projector. 



FREQUENCY IN KC 

Figure 4. Impedance, 5A projector. 



5 A PROJ ECTOR 

: ,j 

Figure 5. 5A projector. 



Figure 3. Receiving response, 5A projector. Figure 6. 5A projector, interior view. 

j Cbiq'IDEy'HAL 




8 


USRL STANDARDS 


^ AX.124 Projector (AX-70) 

Type: ADP Crystal. 

Operating range: 5 to 100 kc. 

Designer: Brush Development Company. 

Reference: USRL Orlando Project 135A, November 21, 1944 to Decem- 
ber 2, 1944. 

Description: This projector, a small model of the AX-63 (see Section 
2.7.40), is designed for maximum output in the region 40 to 50 kc. The 
crystal assembly is split along a vertical axis, and four separate terminal 
connections are brought out from the transducer. The unit is oil-filled so 
that it may be used at depths of several hundred feet. This model super- 
sedes an earlier one, the AX-70, which used X-cut Rochelle salt crystals. 

Efficiency: Approximately — 2 db vs ideal at 55 kc. 




Figure 7. Directivity patterns, AX-124 pro- 
jector at 55 kc. 


180 

Figure 8. Directivity patterns, AX-124 pro- 
jector at 55 kc. Each half measured separately. 





STANDARD INSTRUMENTS 


9 



Figure 9. Transmitting response, AX-124 pro- 
jector. 



Figure 12. Impedance, AX-124 projector. 



Figure 10. Receiving response, AX-124 pro- 
jector. 



I 10 FREQUENCY IN KC 100 

Figure 11. Receiving response, AX-124 pro- 
jector. Each half measured separately. 



Figure 13. AX-124 projector. 




Figure 14. AX-124 projector, interior view. 


[CONFIDENTIAL 



10 


USRL STANDARDS 


^ ^ ^ 2B Projector 

Type: Y-Cut Rochelle Salt Crystal. 

Operating range: 7.5 to 28 kc. 

Designer: Bell Telephone Laboratories. 

Manufacturer : Western Electric Company. 

References: NDRC Report No. 6.1-sr212-625, January 21, 

NDRC Report No. 6.1-sr20-602, January 27, 1943.^® 

Description: A multiunit resonant system using five crystal blocks, each 
covering about 20 per cent of the frequency range. Each block consists of 
quarter wavelength, 45° Y-cut Rochelle salt crystals, backed by a quarter 
wavelength steel resonator. The crystal blocks are enclosed in a chamber 
filled with castor oil. Sound is radiated into the water through a rubber 
dome which forms part of the oil chamber. The rear cover of the unit 
encloses an air chamber containing resonating coils and a step-down 
transformer. 

Overall diameter: 20 in. 

Overall length: 15 in. 

Weight: 217 lb. 

Recommended maximum power input: 6 or 8 w. 

Efficiency: — 3 db at 23 kc. 



STANDARD INSTRUMENTS 


11 



180 ° 


Figure 15. Directivity patterns, 2B projector. 



Figure 16. Impedance, 2B projector. 



Figure 17. Transmitting response, 2B projector. 


16 * 



Figure 18. 2B projector. 


CASTOR OIL FILLED 
CHAMBER / O 


RELAY ASSEMBLY/ Q 


CLAMPING RING 


RUBBER 

DIAPHRAGM 


CRYSTAL- 

BLOCK 



333-A TUBE \6R0NZE 
CASTING 


Figure 19. 2B projector, assembly cross section. 


(jf wFIDENTIAI. 7 




12 


USRL STANDARDS 


^ 3B Projector 

Type: Y-Cut Rochelle Salt Crystal. 

Operating range: 28 to 100 kc. 

Designer: Bell Telephone Laboratories. 

Manufacturer: Western Electric Company. 

References: NDRC Report No. 6.1-sr212-625, January 21, 1943,^^ 
NDRC Report No. 6.1-sr20-602, January 27, 1943.^® 
Description: Similar in principle and construction to BTL 2B projector. 
Overall diameter: 14 in. 

Overall length: 16 in. 

Weight: 124 lb. 

Recommended maximum power input: Varies with frequency from 
about 0.5 w at 100 kc to 5 w at 25 kc. 

Efficiency: Approximately — 3 db at 40 kc. 



OHMS 


STANDARD INSTRUMENTS 


13 



Figure 20. Directivity patterns, SB projector. 


•200 


-400 


-600 


) 




























) 


J\ RESISTANCE 




r 






M 

1 






> 

r- 




i 


Q 

L 






7 







\ 






y 









\ 

rJ 




















~r 

\ 






vJ 


4 



T~ 

f 



\ 





/ 

—L 

\ 


f 

/ 











1 

J- 


\-A 

REACTANCE 








1 


iL 












1 

4— 













1 













i 














' 















FREQUENCY IN KC 
Figure 21. Impedance, SB projector. 



Figure 22. Transmitting response, SB pro- 
jector. 


PROJECTOR 



Figure 2S. SB projector. 


DIAPHRAGM 

CLAMPING 
PING 

CRYSTAL BLOCK 
RESONATOR 



BffON/El 

CASTING 


333-A TUBE 


CONFIDENTIAL 


Figure 24. SB projector, assembly cross section. 

o 




14 


USRL STANDARDS 


' ' " 4B Projector 

Type: Inertia Controlled Moving Coil. 

Operating range: 8 to 500 c. 

Designer: Bell Telephone Laboratories. 

Manufacturer : Western Electric Company. 

Reference: NDRC Report No. 6.1-sr783-1213, November 20, 1943.^^ 

Description: The vibrating surface is an annular-shaped beryllium- 
copper diaphragm covered by a watertight rubber membrane and driven 
by a large moving coil positioned in the field of a permanent magnet. The 
magnet and the diaphragm are enclosed in a cast bronze housing with one 
side of the diaphragm exposed to the water through an opening 9 in. in 
diameter. A high-pressure reservoir at the rear of the projector auto- 
matically supplies air to the rear of the diaphragm to compensate for the 
external water pressure. 

Outside diameter: Approximately 16 in. 

Weight: 375 lb. 

Recommended maximum power input: 125 w from a 16-ohm source. 

Efficiency: Approximately —30 db vs ideal. 

Directional properties: Essentially nondirective in operating frequency 
range. 


STANDARD INSTRUMENTS 


15 



Figure 25. 


100 1000 
FREQUENCY IN CYCLES 

Transmitting response, 4B projector. 



Figure 26. Impedance, 4B projector. 




Figure 27. 4B projector. 


Figure 28. 4B projector, interior view. 




CONFIDENTIAL 


7 



16 


USRL STANDARDS 


^ 6B Projector 

Type: Y-Cut Rochelle Salt Crystal. 

Operating range: 10 to 80 kc. 

Designer: Bell Telephone Laboratories. 

Manufacturer : Western Electric Company. 

Reference: NDRC Report No. 6.1-sr783-1325, August 10, 1944.^^ 

Description: The diaphragm is driven by an array of 45° Y-cut Rochelle 
salt crystals connected in parallel. The crystal array is mounted between 
the diaphragm and a steel backing plate. The rear half of the crystal head 
assembly is enclosed in a casing of a low-impedance, sound-reflecting, 
cork and rubber material. It is designed to work from a circuit having 
135 ohms impedance. A transformer is included in the housing to deliver 
the power from the low-impedance source to the high-impedance crystal 
array. A 25-ft shielded, flexible, 2-conductor, rubber-covered cord is pro- 
vided for connecting the projector to the power source. 

Overall diameter of head: 6l^ in. 

Overall height: 19 V 2 
Weight: 30 lb. 

Recommended maximum power input: 0.1 w from a 135-ohm source. 

Efficiency: Approximately — 16 db vs ideal at 70 kc. 


0® 



180 " 


Figure 29. Directivity patterns, 6B projector. 



Figure 30. Transmitting response, 6B projector. 


ONFIDKNTIAL 



OHMS 


STANDARD INSTRUMENTS 


17 



Figure - 31. Impedance, 6B projector. 



Figure 32. 6B projector. 


crystal 

ARRAY 




Figure 33. Schematic circuit drawing, 6B and 
5 A projectors. 


SHIELDED 
2 CONDUCTOR 
CORD- 


TRANSFORMER 
HOUSING 


METAL-TO- 
GLASS SEALS 


CASE 



CRYSTAL 

HOUSING 


INSULATORS 

DIAPHRAGM 

CRYSTALS 


RESONATOR 


Figure 34. 6B projector, assembly cross section. 


/tONTIDENTIAL j 




18 


USRL STANDARDS 


^ IK Projector 

Type: Inertia Controlled Moving Coil. 

Operating range: 100 to 10,000 c. 

Designer: Bell Telephone Laboratories. 

Manufacturer: Western Electric Company. 

Reference: NDRC Report No. C4-sr212-103, June 1, 1942.^ 

Description: The sound radiating surface is a small piston-type dia- 
phragm with a rigid center and flexible edge. The rigid center, a portion 
of a hemispherical dome of beryllium-copper, is driven at its outer 
perimeter by a moving coil in a high-density magnetic field. The motion of 
the diaphragm is controlled by the combined mass of the vibrating system 
and the loading mass of the water. A rubber compensating chamber auto- 
matically maintains internal air pressure to balance the external water 
pressure at the diaphragm. The unit is designed to work from a circuit 
having 4 ohms impedance. 

Greatest width: 17 in. 

Overall height : 45 in. 

Weight: 150 lb. 

Recommended maximum power input: 


4-ohm source 8-ohm source 


quency 

(c) 

RMS 

open-circuit 

voltage 

Available 

power 

(w) 

RMS 

open-circuit 

voltage 

Available 

power 

(w) 

100 

8.0 

4 

9.4 

2.75 

200 

8.0 

4 

9.0 

2.5 

400 

17.9 

20 

21.6 

14.5 

800 and 
above 

17.9 

20 

21.6 

14.5 


Efficiency when operating from a 4-ohm source: — 26 db vs ideal at 
400 c. 

Directional properties: Nondirectional up to about 2,000 c. Above this 
frequency, uniform through an angle of ±45° from the axis of the 
diaphragm. 



Figure 35. Transmitting response, IK projector. 




STANDARD INSTRUMENTS 


19 



0.1 * ‘ 1.0 
FREQUENCY IN KC 

Figure 36. Impedance, IK projector. 



WATER VENTS 


AIR DUCT 


ELECTRIC CORD 
COMPENSATING BELLOWS 


BRONZE FRONT 


CLAMPING PLATE 
AND RING 


DIAPHRAGM 


.012" BERYLLIUM 
COPPER DIAPHRAGM 


SEALING FLANGE 
AND RING (0.0017") 


MAGNET 

ASSEMBLY 


BRONZE 

ASTING 


BACK 


Figure 37. IK projector, assembly cross sec- 
tion. 



Figure 38. IK projector. 


4 





20 


USRL STANDARDS 


C13 Transducer 

Type: X-Cut Rochelle Salt Crystal. 

Operating range: 5 to 150 kc. 

Designer: Brush Development Company. 

Reference: Brush Report No. LR-118, September 9, 1943.^^ 

Description: An array of X-cut Rochelle salt crystals form a radiating 
area approximately 3 in. square. The unit is oil-filled, which permits its 
use at submerged depths of several hundred feet without appreciable 
change in characteristics. 

Recommended maximum power input: Because of the use of X-cut 
crystals, performance depends on the external circuit used. For stable 
operation a constant current circuit is required. 

Efficiency: — 18.5 db at 70 kc. 



STANDARD INSTRUMENTS 


21 


o» 



I80» 

Figure 39. Directivity pattern, C13 projector 
at 70 kc. 



Figure 40. Transmitting response, C13 pro- 
jector. 



FREQUENCY IN KC 

Figure 41. Impedance, C13 projector. 



Figure 42. C13 projector. 



22 


USRL STANDARDS 


MH Transducers 

Type: X-Cut Quartz Crystal. 

Operating range: 100 to 2,000 kc. 

Designer: Bell Telephone Laboratories. Designed as part of an ultra- 
sonic hydrophone calibration system. 

Manufacturer : Western Electric Company. 

Reference: NDRC Report No. 6.1-sr783-1697, August 17, 1944.^® 

Description: There are two sets of transducers, one for the 100- to 
800-kc range, and one for the 300- to 2,200-kc range. The crystal assembly 
consists of two X-cut quartz crystal disks, silver-treated and soldered one 
on each surface of a steel disk. One side of the assembly vibrates against 
air, the other against a layer of castor oil separated from the water by a 
diaphragm. The crystal disks are 1 cm in diameter in the 300- to 2,200-kc 
instruments, and 3 cm in diameter in the 100- to 800-kc instruments. 

Recommended maximum power input: 3 w. 



PRESSURE AT I METER DISTANCE IN DB VS I DYNE/ SO CM 
WHEN INPUT CURRENT IS I AMPERE 


STANDARD INSTRUMENTS 


23 


o 

0 









































































A. 
















V 


100 TO 8^ 

A /I 

00 K( 

N 1 

: UN 

IIT 










/ 


1 





1 


1 

/ 

* ' 




f\ A 

300 ■ 

ro 220C 

\ I” 

(C 



A 

A 








UNIT 







J 



A 









N/ 


V 

\y 






























































100 1000 10,000 
FREQUENCY IN KC 

Figure 44. Transmitting response, MH trans- 
ducer. 



too TO 800 KC HEAD ^ITH 




30010 \ COUPUNG NETWCW^ HOUaNG-'^YOROPHci'lE FT!E~AMPLIFIE^ i 

?!2O0 KG H£AD^ wrThORAWN FROM HOUSING j 

Figure 46. MH transducer. 



24 


USRL STANDARDS 


lA Hydrophone 

Type: Pressure Gradient Moving Coil. 

Operating range: 100 to 50,000 c. 

Designer: Bell Telephone Laboratories. 

Manufacturer : Western Electric Company. 

Reference: NDRC Report No. C4-sr212-058, March 2, 1942.^ 

Description: A coil consisting of many turns of fine wire wound on a 
rectangular bakelite form is movable in the field of a permanent magnet 
assembly. The entire instrument is suspended by springs in a container 
of thin copper foil with a vulcanized coating of tough rubber. The container 
is filled with an air-free liquid which freezes at 8 F, and which contains 
ethyl alcohol and glycerin in such proportions that the acoustic impedance 
closely matches that of water. Twenty-five feet of shielded, rubber-covered 
cord is connected to the hydrophone. As much as 300 ft of such cord may 
be used between hydrophone and amplifier without appreciable loss or 
distortion. 

Overall dimensions of case: 2x21/2x6 in. 

Weight : 3 lb. 

Directional properties: In a plane perpendicular to the long axis, the 
directivity has a cosine pattern up to about 40 kc. Maximum response is 
obtained when the direction of propagation of the sound is in the plane 
of the coil normal to the longer side. 



Figure 47. Receiving response, lA hydrophone. 


STANDARD INSTRUMENTS 


25 



Figure 48. Calculated threshold, lA hydro- 
phone. 














/ 













/ 












/ 

/ 












/ 

/ 









RE 

:a( 

:tance 


T 










/ 












/ 

/ 


/ 










y 


y 

























RESIST) 

Ince 













— 














UO 10.0 50 

FREQUENCY IN KC 


Figure 50. Impedance, lA hydrophone. 



1 A 

PRESSURE GRADIENT 
HYDROPHONE * 






Figure 49. lA hydrophone. 









I A 

PRESSURE GRADIENT 

hydrophone- 


figure 51. lA hydrophone, interior view. 





26 


USRL STANDARDS 


2A Hydrophone 

Type: Pressure Gradient Moving Coil. 

Operating range: 500 to 100,000 c. 

Designer: Bell Telephone Laboratories. 

Manufacturer : Western Electric Company. 

Reference: USRL Mountain Lakes Project 250 A. 

Description: A smaller model of the lA hydrophone mounted in the 
same size housing. The container is filled with an air-free liquid which 
freezes at 8 F. Twenty-five feet of shielded, rubber-covered cord is con- 
nected to the hydrophone. As much as 300 ft of such cord may be used 
between hydrophone and amplifier without appreciable loss or distortion. 

Overall dimensions of case: 2x21/2x6 in. 

Weight: 3 lb. 

Directional properties: In a plane perpendicular to the long axis, the 
directivity has a cosine pattern up to about 70 kc. Maximum response is 
obtained when the direction of propagation of the sound is in the plane of 
coil normal to the longer side. 



Figure 52. Receiving response, 2A hydrophone. 



THRESHOLD PRESSURE IN DB VS I OYNE/SQ CM 


STANDARD INSTRUMENTS 


27 

































































































































FREQUENCY IN KC 


Figure 53, Calculated threshold, 2A hydro- 
phone. 




















































REACTANCE 

d. 









/ 
















y 















~~ ^ 



RESISTANCE 





























FREQUENCY IN KC 


Figure 55. Impedance, 2A hydrophone. 




2A 

PRESSURE GRADIENT 
HYDROPHONE 


Figure 54. 2A hydrophone. 


Figure 56. 2A hydrophone, interior view. 




28 


USRL STANDARDS 


3A Hydrophone 


Type: Z-Cut ADP Crystal. 

Operating range: 50 to 150,000 c. 

Designer: Bell Telephone Laboratories. 

Manufacturer : Western Electric Company. 

Reference: NDRC Report No. C4-sr212-507, October 1, 1942.^^ 

Description: The latest design uses four 45° Z-cut ADP crystals con- 
nected in parallel and mounted between two diaphragms. The two-stage 
preamplifier is enclosed in a monel metal housing. The amplifier is designed 
to work into a 600-ohm load or transmission line. A 25-ft, 4-conductor, 
shielded cable is supplied with the hydrophone. The maximum output 
voltage that this amplifier can deliver into 600 ohms without overloading is 
approximately 0.2 v, which corresponds to an applied pressure of about 
5,000 to 10,000 dynes per sq cm. The original design employed Y-cut 
Rochelle salt crystals. A special 3A hydrophone for high-pressure measure- 
ments was constructed by shunting the crystal head with a 0.004 ^f con- 
denser. This increased the maximum measurable pressure to 10® dynes 
per sq cm but reduced the response by over 50 db (to about — 140 db vs 1 v 
across 600 ohms per dyne per sq cm). 

A guard is provided for the crystal head. This guard introduces rather 
severe irregularities above 20 kc and in general it is desirable to avoid 
its use in testing. If it must be attached, special care should be taken to 
assure that it is free of air bubbles.^ 

Overall width: 1% in. 

Overall length: III/2 in. 

Diameter of crystal head : % in. 

Directional properties: Response independent of direction of sound inci- 
dence at frequencies less than 15,000 c. Above 15,000 c diffraction affects 
the response when the direction of sound incidence is normal to the dia- 
phragm (at 0°) and it is preferable to use the instrument so that the 
direction of the sound is parallel to the face (90°). 


^ See STR Division 6, Volume 10, Chapter 6. 


STANDARD INSTRUMENTS 


29 




Figure 57. Receiving response, 3A hydrophone. Figure 60. Receiving response, special 3A 

hydrophone. Crystal head shunted with an 0.004 
tii condenser. 


SOLID LINE- HYDROPHONE RESPONSE WITHOUT CAGE 
DOTTED LINE- HYDROPHONE RESPONSE WITH CAGE 



Figure 58. Effect of guard on response of 3A Figure 61. 3A hydrophone, 

hydrophone. 



Figure 59. Measured threshold, 3A hydro- 
phone. 


80,000 

OHMS 



O-B 

I 


Figure 62. Circuit schematic, 3A hydrophone. 


CONFIDENTIAL 




30 


USRL STANDARDS 


AX-91 Hydrophone 


Type: ADP Crystal. 

Operating range: 100 to 100,000 c. 

Designer and Manufacturer : Brush Development Company. 

Reference: USRL Orlando Project 154 A, February 5, 1945 to February 
12, 1945. 

Description: This hydrophone is similar to the Cll-Al hydrophone, 
except that it includes some structural improvements in the assembly of 
the amplifier and head. 


OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF I DYNE /SO CM 


STANDARD INSTRUMENTS 


31 



Figure 63. Receiving response, AX-91 hydro- 
phone. 


z 

o 

o 



u 


f — 1- M m il — I I m il — — 1 — 1— L-LLLLU — I - I III 1 1 

0.01 0.1 1.0 10.0 100.0 
FREQUENCY IN KC 


Figure 64. Measured threshold, AX-91 hydro- 
phone. 



Figure 65. AX-91 hydrophone. 



32 


USRL STANDARDS 


B19-B Hydrophone 


Type: Magnetostriction. 

Operating range: 200 to 100,000 c. 

Designer: Harvard Underwater Sound Laboratory. 

Reference: NDRC Report No. 6.1-srll30-1199, January 17, 1944.^® 
Description: The transducer consists of a nickel tube 35 mils in thickness, 
5% in. in length by 11/2 in. in diameter, with a permanent magnet of 
Alnico metal inside. A semicylindrical wooden core is placed on each side 
of the magnet, and a coil consisting of 130 turns of No. 26 wire is wound 
lengthwise over the core and magnet. The ends of the nickel tube are closed 
by caps fastened together with tie rods. At one end the hydrophone cable 
is brought out through a watertight gland. Suspension yokes are attached 
to the end caps. 



90“ 


180 


Figure 66. Directivity pattern, B19-B hydro- 
phone at 20 kc in a plane perpendicular to the 
axis. 



Figure 67. Directivity pattern, B19-B hydro- 
phone at 70 kc in a plane containing the axis. 





STANDARD INSTRUMENTS 


33 



Figure 68. Receiving response, B19-B hydro- 
phone. 



Figure 70. Impedance, B19-B hydrophone. 



Figure 69. Calculated threshold, B19-B hydro- 
phone. 



Figure 71. B19-B hydrophone. 


NFTDENTIAL 


REACTANCE-OHMS 


34 


USRL STANDARDS 


1 . 4.15 


B19-H Monitor Hydrophone 


Type: Magnetostriction. 

Operating range: 200 to 100,000 c. 

Designer: Harvard Underwater Sound Laboratory. 

Reference: NDRC Report No. 6.1-srll30-1826, August 28, 1944.'^^ 
Description: This unit differs from the B19-B type hydrophone in that 
the tube has a diameter of % in. and a 25-mil annealed nickel wall as com- 
pared to 11/^ in. and a 35-mil nickel wall for the B19-B unit. The mag- 
netostriction assembly is the same as that of the B19-B except that the solid 
Alnico magnet is replaced by four or five 15-mil laminations of Cunico. 



STANDARD INSTRUMENTS 


35 



Figure 72. Directivity pattern, B19-H hydro- 
phone at 40 kc in a plane perpendicular to the 
axis. 



Figure 73. Receiving response, B19-H hydro- 
phone. 


^ -30 

a> 

o 

^ -40 

UJ 

a 

y -50 


i - 60 i 
&) 


I 10 lOO 

FREQUElvTCY IN KC 

Figure 74. Calculated threshold, B19-H hydro- 
phone. 





36 


USRL STANDARDS 


^ ^ 5C and 5E Hydrophones 

Type: 5C Hydrophone: X-Cut Rochelle Salt Crystal. 

5E Hydrophone : Y-Cut Rochelle Salt Crystal. 

Operating range: 5C Hydrophone: 2 to 10,000 c. 

5E Hydrophone : 100 to 40,000 c. 

Designer: Bell Telephone Laboratories. 

Manufacturer : Western Electric Company. 

Reference: NDRC Report No. 6.1-sr346-1321, March 20, 1944.3^ 

Description: Each of these hydrophones consists of a transducer unit 
and an associated two-tube preamplifier contained in a common housing. 
The 5C unit contains eight 45° X-cut Rochelle salt crystals connected in 
parallel; the 5E unit has sixteen 45° Y-cut Rochelle salt crystals. In both 
units the crystals are assembled between a diaphragm, which is exposed to 
the water, and a resonator. The 5C preamplifier is designed to operate with 
600 ohms across the output terminals. The 5E preamplifier is designed to 
operate with 135 ohms across the output terminals. The maximum output 
voltage that this amplifier can deliver into 135 ohms without overloading 
is approximately 1 v at 4 kc, which corresponds to about 15,000 dynes per 
sq cm. (The maximum for the 5C is about 1 v at 2 c and 0.5 v at 10 c into 
600 ohms, about 1,000 dynes per sq cm.) Housings for the two units are 
identical. Twenty-five feet of rubber-insulated cable is provided. Combined 
weight of hydrophone and cord : 12 lb 


4 


STANDARD INSTRUMENTS 


37 



Figure 77. Directivity index, 5C and 5E hydro- 
phones. 



Figure 78. Receiving response, 5C hydrophone. 





50 60 70 80 90 100 

DEGREES FAHRENHEIT 


Figure 81 . Effect of temperature on response 
of 5C hydrophone. 


fCONFIDENTIAL 


38 


USRL STANDARDS 



Figure 83. 5C or 5E hydrophone, interior view. 


AMPLIFIER SOCKET PLUG 
CORD AND PLUG TERMINALS 



Figure 84. Circuit schematic, 5C hydrophone. 



Figure 85. Circuit schematic, 5E hydrophone. 




STANDARD INSTRUMENTS 


39 


SIX CONDUCTOR 
SHIELDED CORD 


GLAND 


HANGERS 


PLUG a SOCKET 
CONNECTION 


PRE-AMPLIFIER 
CHASSIS 

RCA 9000 TYPE 

TUBES 


CRYSTAL CONNECTION 
(LOW SIDE ) 

CRYSTAL CONNECTION 
(HIGH SIDE) 


STEEL RESONATOR 


BERYLLIUM COPPER 

DIAPHGRAM 


ROCHELLE SALT CRYSTAL 



INSULATOR 


Figure 86. 5C or 5E hydrophone, assembly cross 
section. 


CbNFIDENTTAl7~^ 




40 


USRL STANDARDS 


Cll-Al Hydrophone 

Type: X-Cut Rochelle Salt Crystal. 

Operating range: 100 to 100,000 c. 

Designer and Manufacturer : Brush Development Company. 

References: Brush Report No. LR-47, March 4, 1942.“^ 

NDRC Report No. C4-sr20-147, July 27, 1942.’^ 

NDRC Report No. C4-sr20-148, July 27, 1942.8 
NDRC Report No. 6.1-sr20-952, August 30, 1943.203 

Description: The transducer element is a Rochelle salt crystal block, 
in. square by in. long, mounted in a brass ring. The %6-in. faces are 
covered by thin Phosphor bronze diaphragms, which are cemented to 
both the crystal faces and the ring housing. The surface of the crystal 
assembly is chrome-plated. A preamplifier is contained in a cylindrical, 
chrome-plated, brass housing, isolated mechanically from the crystal head 
by a rubber connection. The preamplifier overloads at approximately 
50,000 dynes per sq cm. It is recommended that the resistance across the 
output terminals be 500 ohms. A 28-ft, 5-conductor, shielded cable is 
attached to the preamplifier housing. 

Length: Approximately in. 

Weight: 2% lb. 

Weight of cable: 41/2 lb. 

Directional characteristics: Output of microphone independent of angu- 
lar position below 50,000 c. 


^CONFIDENTIAL' 


OPEN CIRCUIT VOLTS IN OB VS I VOLT 
FOR A SOUND FIELD OF I DYNE/SQ CM 


STANDARD INSTRUMENTS 


41 


-90 


-100 


-110 


-120 


0,1 




' frequency in KC '0 


3v 


1 


100 


Figure 87. Receiving response, Cll-Al hydro- 
phone. 



Figure 88. Measured threshold, Cll-Al hydro- 
phone. 



Figure 89. Cll-Al hydrophone. 



Figure 90. Preamplifier circuit, Cll-Al hydro- 
phone. 


.y:ONFIDENTIAL 



42 


USRL STANDARDS 


Condenser Hydrophone (CMF) 


Type: Condenser. 

Operating range: 0 to 75 c. 

Designer: Massachusetts Institute of Technology. 

References: MIT Research Project D.I.C. 5985, Series Al, No. 12, April 
1 , 1943.18 

NDRC Report No. 6.1-sr20-881, June 30, 1943.^3 

Description: The hydrophone is T-shaped and has two diaphragms lo- 
cated at the ends of the crossbar of the “T."’ The remainder of the housing 
contains a transformer and a pressure equalizing system which com- 
pensates for changes in static pressure. In this compensating system, 
water is led into a chamber surrounding an air-filled rubber bag. The 
pressure on the bag is transferred by means of air ducts to the back of 
the diaphragm. The hydrophone may be calibrated by lowering it to a 
known distance in water with the pressure equalization chamber closed. 

The complete listening system includes, besides the hydrophone with its 
built-in transformer and cable, associated electrical equipment known 
as the Bridge Modulator Model C [BMC] assembly and mounted separately 
in a cabinet 2x19.5x14.5 in. This assembly consists of a Wien impedance 
bridge, oscillator, attenuator, band-pass amplifier, detector, and power 
supply. 

Weight of hydrophone: About 16 lb. 

Weight of BMC cabinet: About 75 lb. 

Directional properties: Essentially nondirective. 



VOLTAGE IN DB VS I VOLT 
FOR A SOUND FIELD OF I DYNE/SO CM 


STANDARD INSTRUMENTS 


43 



FREQUENCY IN CYCLES 


Figure 91. Receiving response, condenser hydro- 
phone. 



Figure 93. Condenser hydrophone, assembly 
cross section. 



Figure 92. Condenser hydrophone. 


WNFIDENTIAir^ 


44 


USRL STANDARDS 


HK Type Hydrophone 

Type: X-Cut Rochelle Salt Crystal. 

Operating range: 20 to 10,000 c, except HKB from 10 to 5,000 c and 
HKC from 2 to 5,000 c. 

Designer: Massachusetts Institute of Technology. 

References: MIT Research Project D.I.C. 5985, Series Al, No. 10, March 
5, 1943.17 No. 13, May 17, 1943.20 
NDRC Report No. 6.1-sr20-879, June 19, 1943.21 
NDRC Report No. 6.1-sr20-881, June 30, 1943.2^ 

Description: The 45° X-cut Rochelle salt crystal head is contained in a 
cylindrical brass case about 2 V 2 in. in diameter and IV 2 in. thick. In the 
original assembly four crystal elements l^xlx% in. were connected 
series parallel. Two metal diaphragms Vs in. thick covered the two ends of 
the crystals exposed to the water. The contact surfaces of the crystal and 
diaphragms were ground optically flat to insure contact over the whole 
area, with only a thin film of cement. Figure 96 shows a typical HK 
hydrophone. 

Associated with the hydrophone is a single-stage preamplifier of the 
cathode-follower type mounted in a cylindrical housing about 1% in. in 
diameter and 10 in. in length. 

Modifications to reduce response variations with temperature were made. 
In particular, a rubber diaphragm was substituted for the metal diaphragm 
in the HKB and HKC models. 

In order to extend the low-frequency range, the connection of crystals 
was changed from series parallel to parallel, thus lowering the impedance 
of the crystal head. In the HKC hydrophone, in addition, the crystal block 
was divided into eight crystals to further lower the impedance. These 
changes and accompanying improvements in the preamplifier design cul- 
minated in the HKC hydrophone which has a uniform response down to 2 c. 


Table 1. Comparison of HK type hydrophones. 


Hydrophone 

model 

Diaphragm 

Crystal 

connections 

Response 

(db)* 

Low-frequency 

droop 

250-20 c 
(db) 

Temperature 
dependence t 
(db) 

20 c 250 c 

Useful 

range 

(c) 

HK 

Brass 

4 in series parallel 

-85 

6-10 

11 

8 

20-10,000 

HKA 

Brass 

4 in parallel 

-90 

2-4 

6 

4 

20-10,000 

HKB 

Rubber 

4 in parallel 

-90 

0 

3 

2 

5-5,000 

HKC 

Rubber 

8 in parallel 

-95 

0 

1.5 

1.5 

2-5,000 


* Approximate response at output of preamplifier. 

t The temperature dependence is measured by the maximum change in response from 0 C to 23.8 C. 


[C^^FITONTIAL ] 


THRESHOLD PRESSURE IN DB VS I OYNE/SQ CM OPEN CIRCUIT VOLTS IN OB VS I VOLT 

I , ^ FOR A SOUND FIELD OF I DYNE /SQ CM 


STANDARD INSTRUMENTS 


45 



FREQUENCY IN KC 


Figure 94 
^lydrophon 


Receiving response, HKB and HKC 



Figure 95. Measured threshold, HKB hydrO' 
phone. 






Figure 96. HK hydrophone. 



Figure 97. HKB hydrophone, assembly cross 
section. 


IMT (FILTERMITE) 



note: circuit can be modified to extend low frequency range. 

OUTPUT TRANSFORMER IS THEN OMITTED. 


Figure 98. Preamplifier circuit, HKB hydro- 
phone. 


) CONtTDENTTAL 



46 


USRL STANDARDS 


OLA Hydrophone 

Type: Tourmaline Crystal. 

Operating range: 8 to 90 kc. 

Designer: Naval Research Laboratory. 

References: NDRC Report No. 6.1-sr20-884, June 28, 1943.^2 

NDRC Report No. 6.1-srll30-2132, January 31, 1945.'^^ 

Description: Four tourmaline disks, each % in. in thickness and 
in. in diameter are cemented together and connected electrically in parallel. 
This stack is backed by a steel plate and a cork sheet. The assembly is 
supported in a spherical steel shell having a sound-transparent rubber 
window and mounted in a cast-bronze housing. The hydrophone is filled 
with castor oil. A 20-ft cable is part of the instrument. 

Weight: Approximately 20 lb. 


THRESHOLD PRESSURE IN DB VS I DYNE/SQ CM 


STANDARD INSTRUMENTS 


47 



Figure 100. Receiving response, OLA hydro- 
phone. 


ISO* 

Figure 99. Directivity pattern, OLA hydro- 
phone at 25 kc. 




Figure 101. Calculated threshold, OLA hydro- 
phone. 


























— 
















X 1 














/ 

1 






RE 

lACTAN 

CE 

7 — 



X' 
























RESISTA,NCE-ll^ 
























0 

-40 

-80 

■120 


Figure 102. Impedance, OLA hydrophone. 



Figure 103. OLA hydrophone. 


CONFIDENTIAL 


REACTANCE- OHMS 



48 


USRL STANDARDS 


^ XMX Hydrophone 

Type: X-Cut Rochelle Salt Crystal. 

Operating range: 300 c to 2,000 kc. 

Designer: Underwater Sound Laboratory, Massachusetts Institute of 
Technology. 

Reference: NDRC Report No. 6.1-srll30-1635, July 11, 1944.^^ 

Description: The crystal head, composed of four 45° X-cut Rochelle salt 
crystals, has dimensions l/4xl^x% in. The assembly is housed in a rec- 
tangular bakelite holder protected by two layers of neoprene. A 5-in. 
cable connects the crystal holder to the cylindrical preamplifier housing. 
The preamplifier is designed to handle, without overloading, output volt- 
ages up to about 7 V corresponding to an applied sound pressure of 
approximately 400,000 dynes per sq cm. Because of its broad frequency 
response, the instrument has been widely used for the measurement of 
aperiodic sounds. 


OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF I DYNE /SO CM 


STANDARD INSTRUMENTS 


49 


o 

0 



Figure 104. Directivity patterns, XMX hydro- 
phone in a plane perpendicular to the axis. 



Figure 105. Receiving response, XMX hydro- 
phone. 



Figure 106. Measured threshold, XMX hydro- 
phone. 



Figure 107. XMX hydrophone. 



Chapter 2 

U. S. NAVY SONAR EQUIPMENTS 


INTRODUCTION 

S ONAR EQUIPMENTS are the underwater eyes 
and ears of U. S. Navy vessels. By their 
use the range and bearing of other vessels or 
of submerged objects can be determined. The 
presence and bearing of moving vessels or 
other noise sources can be detected. Some equip- 
ments scan the ocean bottom and tell the 
depth of the water beneath the vessel. If so 
desired, these equipments will chart the con- 
tour of the bottom over which the vessel passes. 
Sonar equipments also permit underwater tele- 
graphic communication between vessels simi- 
larly equipped. 

For security reasons supersonic frequencies 
(15 to 30 kc), rather than frequencies in the 
sonic range, are used for ranging, sounding, 
and telegraphing. A more directive projector 
beam pattern is obtainable at the higher fre- 
quencies. Listening equipments are designed 
for use in both the sonic and the supersonic 
frequency range. 

The physical characteristics of the under- 
water sound devices which affect the opera- 
tional performance of sonar equipments have 
been outlined.^^^ These pertinent characteris- 
tics are determined for any sonar equipment 
almost wholly by the transducer or projector, 
the associated electronic circuit being of lesser 
importance. Accordingly, the USRL calibra- 
tions of sonar equipments are usually confined 
to projectors and include other apparatus only 
when special functions are involved. 

The quartz sandwich type “oscillator” was 
one of the first projectors used in Great Britain 
for echo ranging. In this country the 19-in. 
spherical magnetostriction-type projector was 
developed. This projector has the advantage of 
simplicity and ruggedness. Rochelle salt crystal 
(JK) units were used for listening. These units 
were in many cases combined with the magne- 
tostriction (QC) unit in the same spherical 
housing. 

The spherical projector, which is used with- 
out a dome, cannot be operated at ship speeds 


greater than about 15 knots because of exces- 
sive noise produced by cavitation of the sur- 
rounding water. Ethylene glycol solution is 
used as an antifreeze liquid in this projector. 
Since this liquid causes considerable transmis- 
sion loss,^^^ present practice in sonar equipment 
design is to place the projectors inside free- 
flooding streamlined domes, which have a 
higher cavitation point. Domes have now been 
designed which have low transmission losses 
and do not seriously affect the projector beam 
patterns. The more recent projectors are, as a 
result, designed for maximum efficiency and 
optimum performance characteristics without 
regard to shape. 

The original JK-type projectors are made 
with X-cut Rochelle salt crystals. Although 
these projectors are efficient over a wide fre- 
quency range, they are subject to variations 
with temperature and are limited in the amount 
of power they will handle.®^ For these reasons, 
their use has been restricted mainly to listening 
systems. Recent advances in the design of pro- 
jectors using ammonium dihydrogen phosphate 
[ADP] crystals now make them suitable for 
use as echo-ranging transducers. This is made 
possible by the temperature independence and 
higher load carrying capacity of the ADP 
crystal. 

Model letters are used generally to identify 
sonar equipments with regard to basic differ- 
ences and purposes of the systems. The equip- 
ments now in service include the following P 

Listening equipments — J series. 

JK. Used in conjunction with QC rang- 
ing. 

JN. Small portable, nondirectional. 

JO and JQ. Use parabolic hydrophones; 
limited number only. 

JP. Uses toroidal M/S hydrophone; JP-1 
uses line M/S hydrophone. 

JT. Improved JP system, uses 5-ft M/S 
line hydrophone. 


^ In this volume, M/S is the abbreviation for magneto- 
striction and R/S for Rochelle salt. 


ECHO-SOUNDING EQUIPMENTS— N SERIES 


51 


Echo-sounding equipments — N series. 

NJ. Range 200 fathoms, separate M/S 
projectors for transmitting and receiving, 
condenser-discharge type driver. 

NK. Range 200 fathoms, two M/S pro- 
jectors in streamlined housing, condenser- 
discharge type driver. 

NM. Heavy-duty M/S type, range up to 
2,000 fathoms. 

Echo-ranging equipments — Q series. 

QB. R/S or ADP crystal projector, 
heavy-duty type. 

QC. M/S projector, heavy-duty type. 
QG. M/S projector, incorporates all 
latest improvements. 

QJ. R/S or ADP projector, incorporates 
all latest improvements. 

Combination ranging, listening, and sound- 
ing — W series. 

WA. M/S projectors. 

WB. R/S or ADP projectors. 

WC. M/S and R/S projectors, M/S 
sounding. 

WD. M/S and R/S or ADP projectors, 
R/S sounding. 

WE. M/S projectors, lightweight. 

The major units in sonar equipments are 
identified by letters and numbers, for example 
CBM 78138. The letters designate the manu- 
facturer (CBM = Submarine Signal Company) 
and the first two numerals the type of equip- 
ment. The last three numerals are assigned in 
the order the requests are received.'" 


2 2 LISTENING EQUIPMENTS— J SERIES 

The original J-series listening equipments 
were designed for use on submarines.®'^ The 
scope of this series has been extended to cover 
equipments for use on small-type picket boats, 
patrol craft. Coast Guard Reserve vessels, etc. 
Listening equipments passed through develop- 
ment stages from straight stethoscope tubes 
to the modern equipments consisting of trans- 
ducers, electronic amplifiers, and reproducing 
apparatus such as recorders, loudspeakers, and 

^ Complete listings are given in Model Letters and 
Type Numbers, Assignment to Naval Radio and Sound 
Equipment (RE 15A lOlJ). 


headphones. The useful listening range has 
been extended to cover supersonic frequencies 
up to about 50 kc. Later type equipments are 
provided with indicating devices which show 
right or left deviation of the bearing of the 
transducer relative to the true bearing of the 
source producing the noise. These indicating 
devices are of various types, including hearing 
deviation indicator [BDI] circuits similar to 
those used in echo ranging, phase actuated 
locator [PAL] systems for use on patrol craft, 
and right-left indicator [RLI] circuits which 
are used in the JT and WFA systems for sub- 
marines.*" 

Calibrations of transducers used in some of 
the listening equipments for U. S. Navy vessels, 
and, in some cases, associated apparatus also, 
have been made by the USRL. References to 
these calibrations are contained in Sections 
2.7.1 to 2.7.6. 


2 3 ECHO-SOUNDING EQUIPMENTS— 

N SERIES 

The function of echo-sounding equipments is 
to measure the depth of water. This is done by 
transmitting a pulse of supersonic energy and 
noting the time required for the echo to return 
from the bottom of the ocean or from a sub- 
merged object as shown in Figure 1. Assum- 
ing the velocity of sound in water to be always 
the same, depth indicators can be calibrated 
directly in fathoms (1 fathom = 6 ft). The 
calibrations are usually based on a sound ve- 
locity of 4,800 fps. 

The pulse is transmitted by a projector 
mounted in the hull of the ship near the keel 
line. The projector normally is mounted flush 
with the outer surface of the hull, facing down- 
ward. The echo is received by the same pro- 

® All the indicating circuits are based on the differ- 
ence in arrival time of sound at the two halves of a 
split hydrophone. In the BDI-type circuit the signals 
from the two halves of the hydrophone are combined so 
as to produce on the screen of a cathode-ray oscilloscope 
a right or left deflection of the electron beam corre- 
sponding to the deviation of the true bearing of the 
target from the training angle of the hydrophone. In 
the PAL and RLI circuits the deviation is indicated 
by positive or negative current readings on a zero- 
center microammeter. 


CONFIDENTIAL j 


52 


U. S. NAVY SONAR EQUIPMENTS 


jector or, in some cases, by a second projector 
similarly mounted and adjacent to the trans- 


TRANSMITTED 
PULSE 



Figure 1. Sound transmission path in echo 
sounding. 



•n 

ECHO 



PROJECTOR 

DEEP 

PROJECTOR 

SHALLOW 


Figure 2. Block diagram, NMC sounding equip- 
ment. 

mitting projector. In most sounding equipments 
the acoustic pulse consists of a short train of 
waves at a supersonic frequency (generally 18, 


20, or 24 kc). In some equipments, for example, 
the NJ type, the pulse consists of a damped 
sinusoidal wave obtained by shock-exciting the 
transmitting projector by means of a con- 
denser discharge. 

The received echo is indicated in three ways : 
(1) as an audio-frequency signal which is fed 
into a loudspeaker, (2) as a radio-frequency 
signal which energizes a neon lamp indicator, 
(3) as voltage to a recorder stylus needle. The 
first method allows aural monitoring. The sec- 
ond method provides a visual indication of the 
depth in fathoms through an aperture in a 
moving belt traveling behind a linear scale 
calibrated in fathoms. The third method per- 
mits a trace to be made on calibrated recorder 
paper corresponding to the depths encountered 



Figure 3. Outline of QJA equipment in ship. 


over a period of time. By this last means a per- 
manent record of the contour of the ocean 
bottom is made. A block diagram of the NMC 
equipment, which is typical of sounding equip- 
ments in general, is shown in Figure 2. Refer- 
ence to calibrations are contained in Sections 
2.7.7 to 2.7.14. 


/i:CN FIDENTIA1 



ECHO-RANGING EQUIPMENTS— Q SERIES 


53 


2-* ECHO-RANGING EQUIPMENTS— 

Q SERIES 

Echo-ranging equipments are used to obtain 
the range and bearing of surface and under- 
water vessels, reefs, buoys, etc. This is done 
hy prejecting a pulse of supersonic energy into 
the water and noting the time required for 
energy reflected from the distant object to re- 
turn as an echo and the direction from which 
such an echo arrives. 

The acoustic pulse, which generally is at a 
frequency in the range from 14 to 30 kc, is 


TYPE CBM-62124 JUNCTION BOX TYPE CBM-62125 JUNCTION BOX 



PROJECTORS MOUNTED ON 
CONCENTRIC SHAFTS 

Figure 4. Functional block diagram, QGA equip- 
ment. 

generated by a projector extending from the 
hull of the vessel. (In some equipments for 
small boats the projector is put into the water 
over the side of the boat.) Except for the 
spherical-type projectors and a few stream- 
lined types, the projector generally is housed 
inside a streamlined dome. The QJA dome 
shown in Figure 3 can be extended when in 
working position and retracted inside a sea 
chest at other times. Some domes are non- 
retractable, that is, they are welded to the hull, 
or ‘^fixed.’^ 

The projector which transmits the pulse is, 
as a rule, also used to receive the echo. The 
received signal is indicated in several ways. 

(1) It is converted to an audible frequency for 
aural monitoring on headphones or loudspeaker. 

(2) The echo is converted to a voltage which 
flashes a neon light traveling over a linear 


scale calibrated directly in yards. This provides 
a visual indication of the range. (3) The re- 
ceived signal is amplified and rectified to pro- 
duce a voltage which is impressed on the stylus 



Figure 5. Functional block diagram, QCJ-2 or 
QCL equipment. 


of a chemical recorder unit. The stylus of this 
unit is caused to travel at constant speed over 
a chemically sensitized paper. A mark is made 
on the paper when the d-c signal voltage is im- 
pressed on the stylus and a calibrated scale is 
used to translate the trace made by the stylus 
on the paper to target range in yards. (4) A 


54 


U. S. NAVY SONAR EQUIPMENTS 


BDI unit is included in many of the systems. 
This permits visual indication on a cathode- 
ray oscilloscope screen of whether the projec- 
tor is trained directly on, or to the right or to 
the left of, the target. When BDI is not used 
(QC reception), the bearing is determined by 
intensity of the received echo. 

Echo-ranging equipments usually are adapted 
for listening in the supersonic frequency range 
to sounds caused by the propellers or other 
moving machinery in vessels, or listening to 
other underwater noise. Usually such equip- 
ments are arranged for telegraphic communi- 
cation with other vessels similarly equipped. 

A functional block diagram of the QGA 
equipment is shown in Figure 4 and of the 
QCJ-2 or QCL equipment in Figure 5. These 
are typical of echo-ranging systems in general 
use. References to calibrations are contained 
in Sections 2.7.15 to 2.7.33. 


2 5 SONAR.RANGING EQUIPMENT— 

W SERIES 

All W-series equipments are combinations of 
systems for ranging, listening, and sounding. 


In some WEA, WEA-1, and WEA-2 equip- 
ments, the 45° inclined baffles installed in the 
domes for use in sounding were found to be 
unsatisfactory and were removed so that these 
equipments could no longer be used for echo 
sounding. All other W-series equipments, how- 
ever, contain the three features outlined. Refer- 
ences to calibrations are contained in Sections 
2.7.34 to 2.7.38. 


EXPERIMENTAL PROJECTORS 


A number of experimental type projectors 
were tested by the USRL. While these instru- 
ments were designed primarily for application 
in sonar equipments, their present status is 
somewhat uncertain. The characteristics of any 
particular one of these instruments may not 
be representative of the eventual product of 
the group. The calibrations of these units, how- 
ever, are of particular interest because of the 
many novel features incorporated in their de- 
sign. References to these calibrations are con- 
tained in Sections 2.7.39 to 2.7.49. 


CONFIDENTIAL 


SONAR EQUIPMENTS 


55 


2 7 SONAR EQUIPMENTS 

JK Sonar-Listening Equipments 

Type: X-Cut Rochelle Salt Crystal. 

Manufacturer : Submarine Signal Company and Radio Corporation of 
America. 

Description: The JK-type equipment is usually used in conjunction with 
QC-type gear. The transducers are Rochelle salt crystal types. The JK-type 
transducers in this report are covered under echo-ranging projectors, as 
the JK crystal unit is usually combined in one housing with a mag- 
netostriction (QC) echo-ranging projector, or is used as the transducer 
in echo-ranging systems in addition to serving as the hydrophone in the 
listening equipment. 


\C0NFIDENTIAt^ 


56 


U. S. NAVY SONAR EQUIPMENTS 


JO Parabolic Hydrophone Assembly (CBD 51035) 

Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer: Brush Development Company, Type 
No. C35. 

Reference: NDRC Report No. C4-sr20-280, September 23, 1942.^^ 

Application: The CBD 51035 is a major unit in the JO listening equip- 
ment for picket boats. The assembly is mounted on the outer surface of 
the hull as a blister-like attachment. Only a limited number of the JO 
equipments are in service. 

Description: The CBD 51035 hydrophone assembly consists of two 
C36-type hydrophones mounted in a rubber-covered blister. The C36 
hydrophone consists of a block of X-cut Rochelle salt crystals mounted in 
the focal plane of a parabolic reflector. The blister is formed of %-in. 
black rubber with a circular window of sound-transparent rubber over 
the mouth of each reflector. 

Impedance of C36 Hydrophone 
At 1 kc = 11 — y45 ohms 
At 5 kc = 5 — y3.5 ohms 

At 10 kc = 7.5 — yi4 ohms 



ISO* 



Figure 6. Directivity pattern, CBD 51035 as- 
sembly at 2 kc. 


Figure 7. Directivity pattern, CBD 51035 as- 
sembly at 5 kc. 


■ /c02s'FIDENTIaD 


SONAR EQUIPMENTS 


57 



Figure 8. Directivity pattern, CBD 51035 as- 
sembly at 9.5 kc. 


Figure 9. Directivity pattern, CBD 51035 as- 
sembly at 18.5 kc. 



Figure 10. Receiving response, C36 hydrophone 
at output of UTC 65856 transformer (approxi- 
mately 40 db voltage gain). Water temperature 
= 74 F. Calculated threshold at 5 kc = approxi- 
mately — 76 db vs 1 dyne/sq cm. 



Figure 11. JO parabolic hydrophone assembly, 
CBD 51035. 


/confidential 



58 


U. S. NAVY SONAR EQUIPMENTS 


JP Sonar-Listening Equipment 

Type: Magnetostriction. 

Designer: Columbia University, Division of War Research, at the U. S. 
Navy Underwater Sound Laboratory, New London, Conn. [CUDWR-NLL] 

Description: Several versions of the JP equipment for submarines are 
in service: 

1. JP. The JP, as originally designed, used a toroidal magnetostrictive- 
type hydrophone and was intended for use on slow-moving district craft. 
Coast Guard Reserve vessels, etc. Calibrations of the toroidal hydrophones 
are given in Sections 6.6.1 to 6.6.6. 

2. JP-1. The JP-1 equipment makes use of a 4-ft line M/S hydrophone 
COG 51053 with a baffle to reduce rear response. USRL calibrations of the 
COG 51053 unit are given in Section 6.6.2. 




60 


U. S. NAVY SONAR EQUIPMENTS 


JQ Sonar-Listening Hydrophone (CBD 51052) 

Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. 6.1-srll30-1190, December 14, 1943.®® 

Application: The CBD 51052 hydrophone was designed for use in the 
JQ listening equipment for Coast Guard Reserve vessels and picket boats. 
Only a limited number of sets have been placed in service. 

Description: The CBD 51052 hydrophone consists of a Rochelle salt 
crystal unit in a parabolic reflector. The unit is located at the approximate 
focal point of the reflector. The crystal unit is connected to the output 
terminals through a step-down transformer. The assembly of the Rochelle 
salt crystal, reflector, and coupling transformer is contained in a Corprene 
and rubber-covered metal housing. Holes through the housing permit the 
reflector to be free-flooded. 

No impedance measurements on this device were made by USRL. 



OPEN CIRCUIT VOLTS IN OB VS 1 VOLT 
FOR A SOUND FIELD OF t OYNE/SQ CM 


SONAR EQUIPMENTS 


61 


90 * 



90 * 90 * 



90 * 


Figure 12. Directivity pattern, JQ hydrophone 
CBD 51052 at 8 kc. 


Figure 13. Directivity pattern, JQ hydrophone 
CBD 51052 at 24 kc. 



Figure 14. Receiving response, JQ hydrophone 
CBD 51052. Water temperature = 58 F. 



£ 


CONFIDENTIAL 



62 


U. S. NAVY SONAR EQUIPMENTS 


Modified JQ Sonar-Listening Hydrophone (CBD 51052) 

Type: ADP Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. 6.1-srll30-1190, December 14, 1943.®® 
Application: This modified CBD 51052 unit is for use in the JQ listening 
system, replacing the Rochelle salt type unit. 

Description: This hydrophone consists of an ADP crystal unit located 
at the approximate focal point of a parabolic reflector. A preamplifier 
couples the crystal unit to the hydrophone output terminals. This pream- 
plifier is included in these calibrations. 

No impedance measurements on this device 'were made by USRL. 



OPEN CIRCUIT VOLTS IN DB VS 1 VOLT 
FOR A SOUND FIELD OF I DYNE/SO CM 
AT THE OUTPUT OF THE PREAMPLIFIER 


SONAR EQUIPMENTS 


63 


0 ® 



180 ® 


Figure 16. Directivity pattern, ADP type CBD 
51052 hydrophone at 8 kc. 



Figure 18. Receiving response, ADP type CBD 
51052 hydrophone. Water temperature = 58 F. 



Figure 17. Directivity pattern, ADP type CBD 
51052 hydrophone at 24 kc. 


CORPRENE OVER 



INTERIOR 

Figure 19. ADP type CBD 51052 hydrophone. 



64 


U. S. NAVY SONAR EQUIPMENTS 


JT Sonar-Listening Equipment 

Type: Magnetostriction. 

Designer: Columbia University, Division of War Research, at the 
U. S. Navy Underwater Sound Laboratory, New London, Conn. 

Description: The JT equipment for submarines is an improved version 
of the JP-1 system. USRL calibrations of the CQA 51074 (NL-124) 
hydrophone, which is the sound pickup unit used in this equipment, are 
contained in Section 6.6.3. 





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66 


U. S. NAVY SONAR EQUIPMENTS 


^ NJ Sonar-Sounding Projector (CBM 78138) 

(Similar to CIP 78138) 

Type: Magnetostriction. 

Designer and Manufacturer : Submarine Signal Company, Type No. 
713C. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: For use on medium and lightweight ships in NJ echo- 
sounding equipment for depths up to 200 fathoms. Its function is to con- 
vert shock impulses from a condenser-discharge type driver to acoustic 
energy in the water. The projector is mounted near the keel of the ship 
with its diaphragm horizontal and in contact with the water. It is located 
adjacent to a similar type unit (CBM 78139), which serves as the receiver. 

Description: The CBM 78138 projector is a magnetostrictive type con- 
sisting of a rectangular laminated nickel stack in a circular housing 
partially filled with oil. The position of the nickel stack is adjustable inside 
the projector housing to allow the active radiating face to be located exactly 
horizontal at the time of its installation on the ship. The projector is 
installed with the arrow on the back of the housing coinciding with the 
shorter dimension of the nickel stack and at right angles to the keel line 
of the ship. Polarization for the projector is furnished by the d-c component 
of the condenser-discharge output of the driver unit. For sketch of device 
see Section 2.7.8. A directivity pattern for the CBM 78138 projector with 
836A driver, measured at peak pressure of pulse, is shown in Figure 20. 
Directivity index = approximately —12 db. Figure 21 gives an analysis of 
the sound field for the CBM 78138 projector with 836A driver. The water 
temperature = 68 F. 

Weight of projector: 110 lb. 



RELATIVE PEAK ACOUSTIC PEAK ACOUSTIC PRESSURE AT 
PRESSURES IN DECIBELS 1 METER IN DBVSIDYNE/CM 


SONAR EQUIPMENTS 


67 


0 “ 



180 * 


Figure 20. Directivity pattern. Broad beam 
pattern — in plane including arrow on case, 
narrow beam pattern— in plane at right angles 
to arrow on case. 


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FREQUENCY IN KC 


Figure 22. CW transmitting response, CBM 
78138 projector. Water temperature = 68 F. 



Figure 21. Analysis of sound field. A. Peak 
acoustic pressure at 1 m. B. Relative peak 
acoustic pressures measured in a 37-c band. 



FREQUENCY IN KC 

Figure 23. Impedance, CBM 78138 projector. 


e^^TDENTlAE' 




68 


U. S. NAVY SONAR EQUIPMENTS 


NJ Sonar-Sounding Projector (CIP 78139) 

(Similar to CBM 78139) 

Type: Magnetostriction. 

Designer: Submarine Signal Company. 

Manufacturer: International Projector Company. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: For use on medium and lightweight ships in NJ echo- 
sounding equipment for depths up to 200 fathoms. It functions in the NJ 
equipment as a receiver to convert the echoes from the sea bottom from 
acoustic to electric energy. The projector is mounted near the keel of the 
ship with its diaphragm horizontal and in contact with the water. It is 
located adjacent to a similar type unit (CIP 78138), which serves as the 
transmitter to send out impulses into the water. 

Description: Except for the impedance of the windings, this projector 
is identical with the CBM (or CIP) 78138 projector. Polarization is fur- 
nished by the residual magnetism provided by a momentary connection of 
3 V dc across the windings. Weight of projector: 110 lb. 

Threshold pressure at resonance : Approximately — 90 db vs 1 dyne per 
sq cm. 


SONAR EQUIPMENTS 


69 




Figure 26. CW receiving response, CIP 78139 
projector. Water temperature = 60 F. Calculated 
threshold at 21.3 kc = — 90 db vs. 1 dyne/sq cm. 


Figure 24. Directivity pattern at 21.34 kc. 
Broad beam — in plane including arrow on case, 
narrow beam — in plane at right angles to arrow 
on case. Directivity index = approximately — 12 
db. 



ARROW POINTS 
PERPENDICULARLY 




Figure 27. NJ sonar sounding projector CBM 
(CIP) 78138 and 78139. 


0. 




CONFIDENTIAL 


70 


U. S. NAVY SONAR EQUIPMENTS 


2.7.9 NMA, NMB-2 Sonar-Sounding Projector (CBM 78067) 

Type: Magnetostriction. 

Manufacturer : Submarine Signal Company, Type No. 763. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: The CBM 78067 projector is used in NM, NMA and 
NMB-2 echo-sounding equipments on submarines and large vessels to 
measure ocean depths up to 4,000 fathoms. Its function is to convert elec- 
tric pulses of approximately 18 kc to acoustic energy and then receive the 
echoes returned from the ocean bottom or other reflecting surface. 

Description: The CBM 78067 projector is a rectangular magnetostrictive- 
type unit with dimensions 101/8x20 in. The projector is mounted by means 
of a flange 13.5x23 in. on the back of the unit. The active driving elements 
are nickel tubes which have one end imbedded in the rectangular steel 
diaphragm. A coil surrounds each nickel tube. These coils carry the d-c 
polarizing current (approximately 9.5 amp) and the pulses of 18-kc driving 
current. 

Impedance at resonance (18.3 kc) : 96 -f yi55 ohms. 

Efficiency at resonance : — 10.0 db vs ideal. 



PRESSURE AT 1 METER IN OB VS I DYNE /SO CM 
PER WATT AVAILABLE POWER FROM 100 OHMS 


SONAR EQUIPMENTS 


71 



90 * 


Figure 28. Directivity patterns, CBM 78067 
projector at 18.3 kc. Directivity index = — 20.8 
db. 



Figure 29. Transmitting response, CBM 78067 
projector. Water temperature = 62 F. Q = 37. 



Figure 30. Receiving response, CBM 78067 
projector. Water temperature — 62 F. Q = 34. 
Calculated threshold at 18.3 kc = — 97 db vs 1 
dyne/sq cm. 





72 


U. S. NAVY SONAR EQUIPMENTS 


2.7.10 NM-5 Sonar-Sounding Projector (CBM 78016A) 

Type: Magnetostriction. 

Manufacturer : Submarine Signal Company, Type No. 551B. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: The CBM 780 16A projector is used in the NM-2, and NM-5 
echo-sounding equipments for medium and large vessels. Its function is to 
convert electric pulses of approximately 18 kc to acoustic energy and then 
receive the echoes returned from the ocean bottom or other reflecting sur- 
face. The projector is mounted in the hull of the ship near the keel with the 
projector diaphragm horizontal. 

Description: The CBM 78016A projector is a magnetostrictive-type unit 
in a cylindrical housing. The active driving elements are a group of nickel 
tubes which have one end imbedded in a circular steel plate serving as the 
diaphragm. A coil surrounds each of these tubes. These coils carry the d-c 
polarizing current (approximately 7.5 amp) and the pulses of 18-kc driving 
current. They also carry the receiving voltage generated when the returning 
echo strikes the diaphragm. Weight of projector: 225 lb. 

Impedance at resonance (18.4 kc) : 126 + ^184 ohms. 

Efficiency at resonance : — 10.5 db vs ideal. 



180 * 


Figure 32. Directivity pattern, CBM 78016A 
projector at 18.7 kc. Directivity index = — 21.7 


db. 


PRESSURE ATI METER IN DB VS 1 DYNE /SO CM 
PER WATT AVAILABLE POWER FROM 100 OHMS 


SONAR EQUIPMENTS 


73 



Figure 33. Transmitting response, CBM 78016A 
projector. Water temperature = 63 F. Q = 45. 



Figure 34. Receiving response, CBM 78016A 
projector. Water temperature = 63 F. Q = 41. 
Calculated threshold at 18.7 kc = — 97 db vs 1 
dyne sq cm. 





Figure 36. CBM 78016A projector. 


P 


/jCO 


NJFIDENTIAL 



74 


U. S. NAVY SONAR EQUIPMENTS 


NMB-1 Sonar-Sounding Projector (CRV 78133) 

Type: Magnetostriction. 

Designer and Manufacturer : RCA Victor Division of the Radio Corpora- 
tion of America, Type No. MI 8983. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: The CRV 78133 is used in the NMB-1 echo-sounding equip- 
ment for large A/S ships for measuring water depths up to 4,000 fathoms. 

Description: The CRV 78133 projector is a magnetostrictive type with 
permanent magnets in a rectangular housing. The active driving elements 
are 170 nickel tubes which have one end imbedded in the heavy rectangular 
steel plate serving as the diaphragm. The coil assembly in the projector 
consists of a series-parallel connection of identical coils over the nickel 
tubes. These coils carry the driving current actuating the projector. Polari- 
zation is produced by 20 permanent magnets in a structure mounted just 
above the nickel tubes. The complete structure is filled with oil up to in. 
from the top plate. Weight of projector: 270 lb. 

Impedance at resonance (18.7 kc) : 42.5 + ^154 ohms. 

Efficiency at resonance (18.7 kc) : — 16.3 db vs ideal. 



Figure 37. Directivity pattern, CRV 78133 pro- 
jector at 18.7 kc. Directivity index = — 16.2 db. 


uQnfidential 


SONAR EQUIPMENTS 


75 



Figure 38. Transmitting response, CRV 78133 
projector. Water temperature = 62 F. Q = 17.8. 


o'' 
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cow -90 




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Figure 39. Receiving response, CRV 78133 pro- 
jector. Water temperature = 62 F. Calculated 
threshold at 18.7 kc = — 86 db vs 1 dyne/sq cm. 


60 


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220 


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10 14 18 22 26 30 

FREQUENCY IN KC 

Figure 40. Impedance, CRV 78133 projector. 



Figure 41A. CRV 78133 projector. 


COIL 



Figure 41B. CRV 78133 projector, component 
parts. 


76 


U. S. NAVY SONAR EQUIPMENTS 


2 . 7.12 


NMC Sonar-Sounding Projectors 
(CRV 78169 and CRV 78170) 


Type: Magnetostriction. 

Manufacturer: Radio Corporation of America, Type MI 16712 A and 
MI 16712B. 

Reference: NDRC Report No. 6.1-srll30-1985, January 16, 1945^- 

Application: These projectors are designed for use in the NMC echo- 
sounding equipment for depths up to 2,000 fathoms. One of the projectors 
is for sounding in shallow water and the other for sounding in deep water. 
The function of the projector in the NMC equipment is to transmit a short 
pulse of 18-kc supersonic energy into the water and then receive the echo 
returned from the ocean bottom or from a reflecting surface. 

Description: The NMC projector is a magnetostrictive type consisting of 
a heavy steel plate or diaphragm in a circular steel housing. Imbedded in 
this plate are 70 nickel tubes which act as driving elements. Above these 
tubes is mounted a permanent magnet. The coil structure in the projector 
consists of a series-parallel connection of identical coils with one such coil 
fitting over each nickel tube. The CRV 78170 projector for deep water 
sounding is filled with CO 2 gas under 6 lb per sq in. pressure. The CRV 
78169 projector for shallow water sounding is identical with the CRV 
78170, except that the CO 2 gas is replaced by oil for damping. 

Efficiency at resonance (CRV 78169) : — 14 db vs ideal. 

Efficiency at resonance (CRV 78170) : — 10 db vs ideal. 



SONAR EQUIPMENTS 


77 



Figure 42. Directivity patterns, CRV 78169 and 
78170. Directivity index: CRV 78169 = — 15.8 
db, CRV 78170 = —14.2 db. 



Figure 44. Receiving response, CRV 78169 and 
78170. Water temperature = 64 F. Q: CRV 78169 
= 22, CRV 78170 = 48. Calculated threshold: 
CRV 78169 at 17.7 kc — — 93 db vs 1 dyne/sq cm, 
CRV 78170 at 17.8 kc = — 89 db vs 1 dyne/sq cm. 



Figure 45. Impedance, CRV 78169 and 78170. 



Figure 43. Transmitting response, CRV 78169 
and 78170. Water temperature = 64 F. Q: CRV 
78169 = 22, CRV 78170 = 47. 



Figure 46. CRV 78169 or 78170 projector. 


CONFIDEN' 


REACTANCE— OHMS 



78 


U. S. NAVY SONAR EQUIPMENTS 


2 . 7.13 


NMC-1 Sonar-Sounding Projector (CBM 78203) 


Type: Magnetostriction. 

Manufacturer: Submarine Signal Company, Type No. 943. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: The CBM 78203 projector is used in the NMC-1 echo- 
sounding equipment for use on ships to measure ocean depths up to about 
4,000 fathoms. Its function is to convert electric pulses of approximately 
18 kc to acoustic energy in the water and then receive the echoes returned 
from the ocean bottom or other reflecting surface. The projector is mounted 
near the keel of the ship with the diaphragm horizontal and in contact with 
the water. 

Description: The CBM 78203 projector is a magnetostrictive type with 
permanent magnets. The active driving elements are 148 nickel tubes which 
have one end imbedded in the heavy circular steel plate serving as the 
diaphragm in contact with the water. Each tube is surrounded by a coil 
which carries the driving current in transmitting the supersonic pulse and 
also the receiving voltage generated when the returning echo strikes the 
diaphragm. The complete structure is fllled with CO 2 gas under 30 lb 
per sq in. pressure. Weight of projector: 140 lb. 

Impedance at resonance (18.4 kc) : 43.2 -j- ^108 ohms. 

Efficiency at resonance : — 11.5 db vs ideal. 


0 * 


90 



Figure 47. Directivity pattern, CBM 78203 pro- 
jector at 18.4 kc. Directivity index = — 16.0 db. 


PRESSURE AT t METER IN DB VS 1 DYNE/SQ CM 
PER WATT AVAILABLE POWER FROM 100 OHMS 


SONAR EQUIPMENTS 


79 



Figure 48. Transmitting response, CBM 78203 
projector. Water temperature = 63 F. Q = 33. 



FREQUENCY IN.KC 


Figure 49. Receiving response, CBM 78203 pro- 
jector. Water temperature = 63 F. Q = 33. 
Calculated threshold at 18.4 kc = — 86 db vs 1 
dyne/sq cm. 


















































































































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FREQUENCY IN KC 

Figure 50. Impedance, CBM 78203 projector. 


HULL RING SUPPLIED 
by INSTALLING YARD 



CaXFIDEXn.Aj. 



80 


U. S. NAVY SONAR EQUIPMENTS 


2.7.14 (WCA-2) Sonar-Sounding Projector (CBM 78214) 

Type: Magnetostriction. 

Designer and Manufacturer : Submarine Signal Company, Type No. 947. 
Reference: NDRC Report No. 6.1-srll30-1837, October 13, 1944.'^^ 
Application: The CBM 78214 projector is used for echo sounding in the 
WCA-2 and the WEB equipments for submarines. Its function is to convert 
electric pulses of approximately 24 kc to acoustic energy in the water and 
then receive the echoes returned from the ocean bottom or other reflecting 
surface. This projector is used in combination with the CBM 78212 echo- 
ranging and listening unit in the WEB equipment and in combination with 
the CBM 78212 and CBM 78213 projectors in the WCA-2 equipment. 

Description: This unit is a magnetostrictive type consisting of a lami- 
nated nickel stack in a rectangular housing. A steel plate % in. thick serves 
as the diaphragm in contact with the water. After assembly the unit is 
filled with an inert gas under pressure of approximately 6 lb per sq in. 
Efficiency at resonance: — 11 db vs ideal. 



Figure 52. Directivity patterns, CBM 78214 
projector at 23.4 kc. Directivity index = — 23.1 
db. 


C yfcoNF IDENTIAi: 


SONAR EQUIPMENTS 


81 



10 100 1 000 
FREQUENCY IN KC 


Figure 53. Transmitting response, CBM 78214 
projector. Water temperature = 82 F. 



Figure 54. Receiving response, CBM 78214 pro- 
jector. Water temperature = 80 F. Q at 23.4 kc 
= 32, at 106.7 kc = 61. Calculated threshold at 
23.4 kc = — 96 db vs 1 dyne/sq cm. 



Figure 55. Impedance, CBM 78214 projector. 




Figure 56. CBM 78214 projector. 


.CONFIDENTIAL 




82 


U. S. NAVY SONAR EQUIPMENTS 


2.7.15 QBE, QBE-1 (JK-9) Sonar-Ranging Projector (CBM 78142) 

Type: X-Cut Rochelle Salt Crystal. 

Manufacturer : Submarine Signal Company, Type No. 865. 

Reference: NDRC Report No. C4-sr20-115, June 20, 1942.^3 
USRL Orlando Project No. 137, January 1945. 

Application: The CBM 78142 projector is used as the transducer in the 
JK-9 sound listening equipment to detect the presence of high-frequency 
underwater sound originating from propellers or other moving machinery 
of vessels. It is also a major unit in the QBE and QBE-1 equipments for 
echo ranging and listening on small A/S ships. The projector is housed in 
a torpedo-shaped, or fish-type, retractable dome. 

Description: The CBM 78142 projector is banjo-shaped, approximately 
131/2 in. in diameter by 5 in. deep. The active elements, consisting of X-cut 
Rochelle salt crystals, are mounted on a steel backing plate. The space 
between the crystals and the projector face is filled with air-free dehydrated 
castor oil. The crystals are connected in parallel. This projector is not 
arranged for BDI. When this type unit is split for BDI operation, it is 
coded CBM 78142A (865A). 

No transmitting response on this device was taken by USRL. 

Efficiency at 24 kc : — 3.7 db vs ideal. 


% 


fcQNFIDEj ^J^LN 


OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF 1 DYNE /SO CM 


SONAR EQUIPMENTS 


83 



180 * 


Figure 57. Directivity patterns, CBM 78142 pro- 
jector. Directivity index: at 20 kc = — 20.2 db, 
at 24 kc = —21.7 db, at 28 kc = —23.3 db. 



Figure 58. Receiving response, CBM 78142 pro- 
jector. Water temperature = 62 F. Calculated 
threshold at 20 to 28 kc = — 102.5 db vs 1 
dyne/sq cm. 


I 





84 


U. S. NAVY SONAR EQUIPMENTS 


2.7.16 QBE-2, QBE-3 Sonar-Ranging Projector (CBM 78142A) 

Type: X-Cut Rochelle Salt Crystal. 

Manufacturer: Submarine Signal Company, Type No. 865A. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: The CBM 78142 A projector is used as a topside transducer 
in the QBE-2 equipment for submarines and is a major unit in the QBE-3 
equipment for small A/S ships. When used with the QBE-3 equipment, the 
projector is housed in a torpedo-shaped, or fish-type, retractable dome. 

Description: The CBM 78142A projector is a banjo-shaped transducer 
approximately 131/2 in. in diameter by 5 in. deep. The active elements, 
consisting of X-cut Rochelle salt crystals, are mounted on a steel backing 
plate. The space between the crystals and the projector face is filled with 
air-free dehydrated castor oil. The crystals are connected in parallel and 
the unit is split for BDI operation. This unit is similar to the CBM 78142 
(865) projector, except that the latter is not arranged for BDI. 

Efficiency at 24 kc : — 3.7 db vs ideal. 




NFIDENTIAI. 




PRESSURE AT I METER IN DB VS I DYNE/SQ CM 
PER WATT AVAILABLE POWER FROM 100 OHMS 


SONAR EQUIPMENTS 


85 



Figure 60. Directivity patterns, CBM 78142A 
projector. Directivity index: at 20 kc = — 21.2 
db, at 24 kc = — 22.5 db, at 28 kc = — 24.2 db. 



Figure 61. Transmitting response, CBM 78142A 
projector. Water temperature = 62 F. 



Figure 62. Receiving response, CBM 78142A 
projector. Water temperature = 62 F. Calculated 
threshold at 20 to 28 kc = — 103 db vs 1 dyne/sq 
cm. 




86 


U. S. NAVY SONAR EQUIPMENTS 


QBE Sonar-Ranging Projector (CW 78178) 

Type: 45° Y-Cut Rochelle Salt Crystal. 

Designer: Bell Telephone Laboratories. 

Manufacturer : Western Electric Company, Type No. D-163462. 

Reference: NDRC Report No. 6.1-srll30-1634, July 5, 1944.®* 

Application: The CW 78178 unit is used as the projector in QBE, QJA, 
or QJB echo-ranging equipments for ranging on objects at distances up to 
10,000 yd. The CW 78178 projector is interchangeable with the CW 78207 
projector. 

Description: The active elements in the CW 78178 projector consist of 
45° Y-cut Rochelle salt crystals mounted on a steel plate with resonators 
to sharpen the tuning. The projector is rectangular in shape and is intended 
for use in a retractable-type dome. The active area in contact with the 
water is approximately 101/^x10)4 in. The CW 78178 is a four-wire 
projector split for BDI operation with the electrical connections to each 
half of the projector brought out separately. Weight: Approximately 200 lb. 

Efficiency at 24 kc : — 3.6 db vs ideal. 



Figure 64. Directivity pattern, CW 78178 pro- 
jector at 24 kc. Connected parallel aiding. Di- 
rectivity index = — 23.4 db. 




SONAR EQUIPMENTS 


87 



Figure 65. Transmitting response, CW 78178 
projector. Connected parallel aiding. Water 
temperature = ‘46 F. 



Figure 66. Receiving response, CW 78178 pro- 
jector. Connected parallel aiding. Water temper- 
ature = 46 F. Calculated threshold at 24 kc = 
— 102.5 db vs 1 dyne/sq cm. 



Figure 67. Impedance, CW 78178 projector. 
Connected parallel aiding. 



Figure 68. CW78178 projector. 


REACTANCE— OHMS 




88 


U. S. NAVY SONAR EQUIPMENTS 


QBG Sonar-Ranging Projector (CFF 78187) 

Type: 45° X-Cut Rochelle Salt Crystal. 

Manufacturer : Freed Radio Corporation. 

Reference: NDRC Report No. 6.1-sr20-941, July 21, 1943.^^ 

Application: The CFF 78187 projector is a major unit in the QBG 
echo-ranging equipment for landing craft. The unit is tiltable and, when 
trained vertically downward, may be used for depth sounding. In the 
QBG equipment the projector is shock-driven by a condenser-discharge 
type driver and operates in the 22 to 26 kc range. The projector is used for 
both transmitting and receiving. It is preferably mounted in a well in the 
boat but may be hung over the side. This unit normally is used in a 
torpedo-shaped dome. 

Description: This projector consists of a number of 45° X-cut Rochelle 
salt crystal units )4xlxl% in. mounted on a heavy plate. Cork spacers are 
inserted between the crystal units. The driver unit is designed to operate 
from one 6-v, 120-amp-hr storage battery with a genemotor or Vibropack, 
or it may be run from dry batteries. 

Efficiency at 25 kc : — 5 db vs ideal. 


/'ONFIDENTIAlV 


SONAR EQUIPMENTS 


89 


o« 



/ 

. / 



i 

L 

r 

1 



Figure 69. Directivity patterns, CFF 78187 pro- 
jector. Directivity index: at 22 kc = — 17.3 db, 
at 25 kc = — 18.5 db. 



Figure 71. Receiving response, CFF 78187 pro- 
jector. Water temperature = 78.5 F. Calculated 
threshold at 22 to 26 kc = — 98 db vs 1 dyne/sq 
cm. 



Figure 72. Impedance, CFF 78187 projector. 



Figure 70. Transmitting response, CFF 78187 
projector. Water temperature = 78.5 F. 



Figure 73. CFF 78187 projector. 



REACTANCE-OHMS 


90 


U. S. NAVY SONAR EQUIPMENTS 


2.7.19 QCA (QCB) Sonar-Ranging Projector (CBM 78017) 

Type: Magnetostriction. 

Manufacturer : Submarine Signal Company, Type 550C. 

Reference: NDRC Report No. 6.1-srll30-1194, December 28, 1943.®^ 
USRL Orlando Project No. 137, January 1945. 

Application: The CBM 78017 projector is used as a major unit in QC-1, 
QC-IA, in QCA, QCA-1, and in QCB, QCB-1, QCB-2, QCB-3 sonar equip- 
ment. These equipments are used on destroyers and on other large A/S 
ships for echo ranging on distant objects and for telegraphic communica- 
tion between vessels similarly equipped. 

The projector is mounted in a sea chest on a tubular shaft. An elec- 
trically operated hoist permits the projector to be lowered and trained 
in a horizontal direction while the system is in use and to be withdrawn 
into the sea chest at other times. 

Description: The CBM 78017 projector is a magnetostrictive-type unit 
in a spherical housing. The active elements are nickel tubes which have 
one end imbedded in a steel plate serving as the diaphragm. A coil sur- 
rounding each nickel tube carries both the d-c polarizing current and 
pulses of the 24-kc operating current supplied by the driver unit. The 
projector is not split for BDI operation. The diaphragm is covered by a 
hemispherical shell of stainless steel, and the cavity is filled with a mixture 
of ethylene glycol and water. Weight of projector: 375 lb. 

Efficiency at 25 kc : — 14.5 db vs ideal. 



Figure 74. Transmitting response, CBM 78017 Calculated threshold at 22.8 kc = — 91.5 db vs 

projector. Water temperature =: 60 F. Q = 11.5. 1 dyne/sq cm. 


^Confidentia: 


SONAR EQUIPMENTS 


91 



Figure 76. Directivity pattern, CBM 78017 pro- 
jector at 22.8 kc. Directivity index = — 21.9 db. 






Figure 78B. CBM 78017 projector, component 
Figure 78A. CBM 78017 projector. parts. 


? [^NFIDENTIAL 



92 


U. S. NAVY SONAR EQUIPMENTS 


QCJ Sonar-Ranging Projector (CBM 78099) 

Type: Magnetostriction. 

Manufacturer: Submarine Signal Company, Type No. 550L. 

Reference: BTL Reports of March 18, 23, 27, 1942 .^®> 

Application: The CBM 78099 projector is used in the QCJ-3, QCJ-4, 
QCJ-5, and QCJ-6 echo-ranging equipments for large A/S ships. It oper- 
ates at a frequency of 24 kc and is mounted on the starboard side of the 
ship. A similar type projector, the CBM 78098, operating at a frequency 
of 20 kc, is mounted on the port side of the ship as a major unit in the 
QCL equipment. 

Description: The CBM 78099 projector is a magnetostrictive type in a 
19-in. spherical housing. The active elements are a number of nickel tubes 
which have one end imbedded in a steel plate serving as the diaphragm. 
A coil over each tube carries d-c polarizing current and the pulses of 24-kc 
driving current. The unit is not arranged for BDI. A hemispherical steel 
cover fastens over the diaphragm, and the cavity is filled with a mixture 
of ethylene glycol and water. 

Impedance at resonance (tuned) : 148 + ^5.5 ohms. 

Efficiency at resonance: — 11 db vs ideal. 


( f :0.\FIDEXTIAL ] 


SONAR EQUIPMENTS 


93 


0 * 



180 * 

Figure 79. Directivity pattern, CBM 78099 pro- 
jector at 23.5 kc. Directivity index = — 22.1 db. 



Figure 80. Tuned transmitting response, CBM 
78099 projector. Water temperature = 62 F. Q = 
25. 



10 20 30 

FREQUENCY IN KC 


Figure 81. Tuned receiving response, CBM 
78099 projector. Water temperature = 62 F. Q = 
25. Calculated threshold at 23.5 kc = — 94 db vs 
1 dyne/sq cm. 


UCONFIDENT^L ] 



94 


U. S. NAVY SONAR EQUIPMENTS 


QCJ-9 Sonar-Ranging Projector (CBM 78183) 

Type: Magnetostriction. 

Manufacturer: Submarine Signal Company, Type No. 550W. 

Reference: NDRC Report No. 6.1-srll30-1196, January 4, 1944.®^ 
USRL Orlando Project No. 137, January 1945. 

Application: The CBM 78183 projector is a major unit in the QCJ-9 
sonar equipment used on large A/S ships for echo ranging on distant 
objects. The unit operates at 24 kc. It is used without a dome. 

Description: This projector is a magnetostrictive-type unit in a spherical 
housing approximately 19 in. in diameter. The active elements are a 
group of nickel tubes attached at one end to a circular steel plate serving 
as the diaphragm. The nickel tubes are polarized by a d-c field and vibrate 
under the influence of a 24-kc field supplied by the driver for transmitting 
acoustic pulses into the water. The unit functions also as a receiver to 
convert acoustic pulse echoes to electric energy. 

A hemispherical stainless steel cover fastens over the diaphragm and 
the cavity between the diaphragm and cover is filled with a 50 per cent 
solution of ethylene glycol and water. 

A filter junction box, through which the d-c polarizing current of 
approximately 7 amp is supplied, is included as an integral part of the 
projector in these data. 

Efficiency at resonance (24 kc) : — 19 db vs ideal. 



90 * 


ISO* 


Figure 82. Directivity pattern, CBM 78183 pro- 
jector at 24.4 kc. Directivity index = — 22.9 db. 


jtONFIDENTIALj 


SONAR EQUIPMENTS 


95 



Figure 83. BDI patterns, CBM 78183 projector 
at 24.4 kc. Electrical phase shift = 80°. 



Figure 84. Transmitting response, CBM 78183 
projector. Water temperature = 61 F. Q = 29.5. 



Figure 85. Receiving response, CBM 78183 pro- 
jector. Water temperature = 61 F. Q = 22.5. 
Calculated threshold at 24.4 kc = — 86 db vs 1 
dyne/sq cm. 






96 


U. S. NAVY SONAR EQUIPMENTS 


QCL Sonar-Ranging Projector (CRV 78103) 

Type: Magnetostriction. 

Manufacturer : Radio Corporation of America. Type No. MI 8943-2. 

Reference: BTL Reports of March 18, 23, 27, 1942 .^^- 

Application: This projector is a major unit in QCL and QCL-7 sonar 
equipments used on large A/S vessels for echo ranging on distant objects. 
Early models of this projector were not arranged for BDI. This unit oper- 
ates at 20 kc. 

A similar type projector with a nominal operating frequency of 24 kc 
is coded CRV 78104 (MI 8943-1) and is used in QCJ-2 and QCJ-8 equip- 
ments. When both the QCL and the QCJ equipments are installed on the 
same vessel, the QCL (20 kc) equipment is normally installed on the port 
side and the QCJ (24 kc) equipment on the starboard side. 

Description: The CRV 78103 projector is a magnetostriction unit in a 
spherical housing. A heavy steel plate mounted in the housing serves as 
the diaphragm. Imbedded in this plate are 319 nickel tubes which act as 
the driving elements. In this unit the nickel tubes and diaphragm are 
mechanically tuned to resonate at approximately 20 kc. The coil structure 
consists of a series-parallel arrangement of identical coils with one coil 
surrounding each tube. These coils carry both the d-c polarizing current 
(approximately 7 amp) and the high-frequency driving currents. The 
diaphragm is covered by a hemispherical shell of stainless steel, and the 
cavity is filled with an ethylene glycol solution. The back cover consists 
of a hemispherical shell of cast iron. The projector weighs approximately 
490 lb. 

A filter junction box having 0.01 fxi across projector winding and 0.08 
/xf between each side projector winding and driving or receiving amplifier 
is included as an integral part of this projector in these data. 

Impedance at 20.5 kc: 34 — ^69.5 ohms. 

Efficiency at 20.5 kc: — 10.1 db vs ideal. 


r^^ONFIDENTIAL ,| 


SONAR EQUIPMENTS 


97 



180 


Figure 87. Directivity pattern, CRV 78103 pro- 
jector at 20.5 kc. Directivity index = — 21.4 db. 



Figure 89. Receiving response, CRV 78103 pro- 
jector including junction box. Water tempera- 
ture = 62 F. Q = 100. Calculated threshold at 
20.5 kc =: — 95 db vs 1 dyne/sq cm. 



FREQUENCY IN KC 

Figure 88. Transmitting response, CRV 78103 
projector including junction box. Water temper- 
ature = 62 F. Q = 100. 



Figure 90. CRV 78103 projector. 


CONFIDENTIAL 



98 


U. S. NAVY SONAR EQUIPMENTS 


QCL-8 Sonar-Ranging Projector (CBM 78182) 

Type: Magnetostriction. 

Manufacturer : Submarine Signal Company, Type No. 550V. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: The CBM 78182 projector is used in the QCL-8 echo-rang- 
ing equipment for large A/S ships. The projector is used without a dome. 

Description: The CBM 78182 is a 19-in. diameter spherical-shaped 
magnetostriction transducer. The active elements consist of nickel tubes 
attached at one end to a circular steel plate serving as the diaphragm. 
The tubes are polarized by direct current flowing through coils surround- 
ing them. A total magnetizing current of from 7 to 8 amp is required. 
These same coils carry the pulses of 20-kc energy supplied by the driver. 
The unit is diametrically tapered, that is, the tubes close to the vertical 
diameter are driven at higher amplitudes than those farther away. This 
projector is split for BDI operation; otherwise it is similar to the CBM 
78098 (550M). 

A hemispherical steel cover fastens over the diaphragm, and the cavity 
between diaphragm and cover is filled with a 50 per cent solution of 
ethylene glycol and water. 

Efficiency at resonance: — 19 db vs ideal. 



Figure 91. Directivity pattern, CBM 78182 pro- 
jector at 20.5 kc. Connected parallel aiding. Di- 
rectivity index = — 21.2 db. 


PRESSURE AT I METER IN OB VS 1 DYNE/SQ CM 
PER WATT AVAILABLE POWER FROM 100 OHMS 


SONAR EQUIPMENTS 


99 



90 * 


Figure 92. BDI patterns, CBM 78182 projector 
at 20.5 kc. Electrical phase shift = 68.5°. 



FREQUENCY IN KC 

Figure 93. Transmitting response, CBM 78182 
projector. Connected parallel aiding. Water 
temperature = 61 F. Q = 43. 



Figure 94. Receiving response, CBM 78182 pro- 
jector. Connected parallel aiding. Water temper- 
ature = 61 F. Q = 25. Calculated threshold at 
20.5 kc = — 91.2 db vs 1 dyne/sq cm. 



CO^DENTIAi:;a 




100 


U. S. NAVY SONAR EQUIPMENTS 


2.7.24 QCN Sonar-Ranging Projector (CBM 78115) 

Type: Combination Magnetostriction and Rochelle Salt Crystal. 

Manufacturer: Submarine Signal Company, Type No. 733F. 

Reference: NDRC BTL Reports of March 18, 23, 27, 1942.40. 4i, 42 

Application: The CBM 78115 projector is a major unit in QCN-1, 
QCN-2, or QCN-3 sonar equipments. These equipments are used on large 
A/S ships for echo ranging on distant objects, telegraphic communication 
with other ships similarly equipped, and for listening to high-frequency 
sounds produced by other ships. This projector operates at 24 kc and is 
not arranged for BDI. When this type projector is arranged for BDI 
operation, it is coded CBM 78184 (733K) and is used in the QCN-4 
equipment. 

A similar type projector with a nominal operating frequency of 20 kc 
is coded CBM 78116 (733G) and is used in QCO, QCO-1, or QCO -2 equip- 
ments. When arranged for BDI this unit is coded CBM 78185 (733L) and 
is used in the QCO-3 equipment. When both 20-kc and 24-kc equipments are 
installed on the same ship, the QCN (24 kc) equipment is normally in- 
stalled on the starboard side and the QCO (20 kc) equipment on the port 
side. 

Description: The CBM 78115 projector is a combination magnetostriction 
unit and a Rochelle salt crystal unit in a spherical housing. 

The magnetostriction unit or QC face consists of a group of nickel tubes 
which are attached at one end to the circular steel plate serving as the 
diaphragm. The nickel tubes are polarized by a d-c field and vibrate under 
the infiuence of an a-c field supplied by the driver for transmitting acoustic 
pulses into the water. The unit functions also as a receiver to convert the 
acoustic pulse echoes returned from distant objects in the water into electric 
energy. The diaphragm is covered by a hemispherical shell of stainless 
steel, and the cavity is filled with a 50 per cent mixture of ethylene glycol 
and water. 

A filter junction box having 0.01 /xf across projector and 0.06 /xf between 
each side projector winding and driving or receiving amplifier is included 
as an integral part of the QC unit in these data. 

The Rochelle salt crystal unit or JK face is used for listening to high- 
frequency noises generated by propellers and other moving parts of dis- 
tant vessels. This unit consists of a number of blocks of Rochelle salt 
crystals mounted on a heavy steel back plate. A hemispherical rubber shell 
encloses the unit, and the cavity between the crystal blocks and the rubber 
shell is filled with technical castor oil. Weight of projector: 560 lb. 

Impedance: QC face at 24 kc: 168 -f ^43 ohms. 

JK face at 35 kc : 630 — /1 120 ohms. 

Efficiency: QC face at resonance (24 kc) : — 15 db vs ideal. 

JK face at 25 kc : — 1.6 db vs ideal. 


E 


confidentia; 


SONAR EQUIPMENTS 


101 



90 “ 


Figure 96. Directivity pattern, CBM 78115 pro- 
jector at 23.8 kc. M/S unit, including junction 
box. Directivity index = — 22.4 db. 



Figure 97. Directivity pattern, CBM 78115 pro- 
jector at 25 kc. R/S unit. Directivity index = 
—23.1 db. 




Figure 98. Transmitting response, CBM 78115 

projector. M/S unit, including junction box. Figure 99. Transmitting response, CBM 78115 

Water temperature = 62 F. Q = 35. projector. R/S unit. Water temperature = 62 F. 


|c6nfident]JU.) I 




OPEN CIRCUIT VOLTS IN OB VS 1 VOLT 
FOR A SOUND FIELD OF I DYNE/SO CM 


102 


U. S. NAVY SONAR EQUIPMENTS 



10 


20 


30 

FREQUENCY IN KC 


40 


Figure 100. Receiving response, CBM 78115 
projector. M/S unit, including junction box. 
Water temperature = 62 F. Q = 35. 



Figure 101. Receiving response, CBM 78115 
projector. R/S unit. Water temperature = 62 F. 



Figure 102A. CBM 78115 projector. 


Figure 102B. CBM 78115 projector, component 
parts. 



SONAR EQUIPMENTS 


103 


QCN-4 Sonar-Ranging Projector (CBM 78184) 

Type: Combination Magnetostriction and Rochelle Salt Crystal. 

Manufacturer : Submarine Signal Company, Type No. 733K. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: The CBM 78184 projector is a combination echo-ranging 
and listening unit. It is a major unit in the QCN-4 sonar equipment for 
large A/S ships. 

Description: The CBM 78184 projector is a combination magnetostric- 
tion unit and a Rochelle salt unit in a 19-in. diameter spherical housing. 

The magnetostriction unit consists of a group of nickel tubes which are 
attached at one end to the circular steel plate serving as the diaphragm. 
The nickel tubes are polarized by a d-c field and vibrate under the influence 
of 24-kc a-c field supplied by the driver for transmitting acoustic pulses 
into the water. The unit functions also as a receiver to convert acoustic 
echoes into electric energy. The diaphragm is covered by a hemispherical 
shell of stainless steel, and the cavity is filled with a 50 per cent mixture 
of ethylene glycol and water. The unit is split for BDI operation. Other- 
wise this projector is similar to the CBM 78115 (733F) projector. 

The Rochelle salt crystal unit is used for listening to high-frequency 
noises generated by propellers and other moving parts of distant vessels. 
This unit consists of a number of blocks of Rochelle salt crystals mounted 
on a heavy steel backing plate. A hemispherical rubber shell encloses the 
unit and the cavity between the crystal blocks and the rubber shell is filled 
with technical castor oil. 

Efficiency: M/S unit (24 kc) : — 11 db vs ideal. 

R/S unit (24 kc) : — 3.5 db vs ideal. 



PRESSURE ATI METER IN DB VS 1 DYNE /SO CM 
PER WATT AVAILABLE POWER FROM tOO OHMS 


104 


U. S. NAVY SONAR EQUIPMENTS 




Figure 104. Directivity patterns, CBM 78184 
projector. R/S unit. Directivity index at 20 kc 
= —22.0 db, at 24 kc = —23.5 db, at 28 kc 
= —25.0 db. 


Si 

q: 


TO K50“ 

FREQUENCY IN KC 


Figure 106. Transmitting response, CBM 78184 
projector. R/S unit. Water temperature = 61 F. 


180* 

Figure 103. Directivity pattern, CBM 78184 
projector at 24 kc. M/S unit. Connected parallel 
aiding. Directivity index = — 21.7 db. 


* *°frequency in kc 

Figure 105. Transmitting response, CBM 78184 
projector. M/S unit. Connected parallel aiding. 
Water temperature = 61 F. Q = 60. 



SONAR EQUIPMENTS 


105 




Figure 107. Receiving response, CBM 78184 
projector. M/S unit. Connected parallel aiding. 
Water temperature = 61 F. Q = 55. Calculated 
threshold at 24 kc = — 94.4 db vs 1 dyne/sq cm. 


Figure 108. Receiving response, CBM 78184 
projector. R/S unit. Water temperature = 61 F. 
Calculated threshold at 24 kc = — 103.8 db vs 1 
dyne/sq cm. 



Figure 109. Impedance, CBM 78184 projector. 
M/S unit. 



Figure 110. Impedance, CBM 78184 projector. 
R/S unit. 


'\CONFIDENTIAir] 


106 


U. S. NAVY SONAR EQUIPMENTS 


QCO-3 Sonar-Ranging Projector (CBM 78185) 

Type: Combination Magnetostriction and Rochelle Salt Crystal. 

Manufacturer : Submarine Signal Company, Type No. 733L. 

Reference: NDRC Report No. 6.1-srll30-1368, March 6, 1944.^® 

USRL Orlando Project No. 137, January 1945. 

Application: The CBM 78185 projector is a combination echo-ranging 
and listening unit. It is a major unit in the QCO-3 sonar equipment 
for large A/S ships. 

Description: The CBM 78185 projector is a combination of a magneto- 
striction unit and a Rochelle salt unit mounted back to back in a 19-in. 
diameter spherical housing. 

The M/S unit operates at approximately 20 kc. It is similar to the QCO, 
QCO-1, QCO-2 projector CBM 78116 (733G), with the exception that it is 
parallel-split for BDI operation. It is also similar to the CBM 78184 (733K) 
projector used in the QCN-4 equipment, except that the latter unit is 
designed to operate at 24 kc. 

Efficiency at resonance: M/S unit: — 17 db vs ideal. 

R/S unit: See Section 2.7.25. 




CONFIDENTIAL 


PRESSURE AT 1 METER IN DB VS 1 DYNE /SO CM 
PER WATT AVAILABLE POWER FROM 100 OHMS 


SONAR EQUIPMENTS 


107 


0 “ 



Figure 111. Directivity pattern, CBM 78185 
projector at 20.7 kc. M/S unit. Directivity index 
—21.2 db. 



Figure 112. Transmitting response, CBM 78185 
projector. M/S unit. Connected parallel aiding. 
Water temperature = 61 F. Q = 20. 










































































1 





r 












\ 







3 




/ 

\ 











TT 














\ 






D 






V 





























10 

FREQUENCY IN KC 


Figure 118. Receiving response, CBM 78185 
projector. M/S unit. Connected parallel aiding. 
Water temperature = 61 F. Q = 14. Calculated 
threshold at 20.7 kc = — 86 db vs 1 dyne/sq cm. 



Figure 114. Impedance, CBM 78185 projector. 
M/S unit. 


( confideI^tal j 



108 


U. S. NAVY SONAR EQUIPMENTS 


QCQ Sonar-Ranging Projector (CBM 78145) 

Type: Magnetostriction. 

Manufacturer: Submarine Signal Company, Type No. 880. 

Reference: NDRC Report No. 6.1-sr20-887, July 6, 1943.®® 

NDRC Report No. 6.1-sr20-948, August 16, 1943.®^ 

Application: The CBM 78145 projector is a major unit in the QCQ, 
QCQ-3 echo-ranging equipments for large A/S vessels. It operates at a 
frequency of 24 kc. A similar type unit, CBM 78146 (880A) , which operates 
at a frequency of 20 kc, is a part of the QCR, QCR-2 equipment. The QCQ 
projector is normally mounted on the starboard side of the ship and the 
QCR projector on the port side. 

Description: The CBM 78145 projector is a magnetostrictive type in a 
banjo-shaped housing 17 in. in diameter by 5% in. deep. The vibrating 
element is a group of nickel tubes attached at one end to a circular steel 
plate serving as the diaphragm. A coil surrounding each tube carries the 
d-c polarizing current and the pulses of 24-kc alternating current supplied 
by the drive. The unit functions also to receive the echoes returned from 
any reflecting surface such as a distant submarine or vessel. 

Impedance at 24.2 kc tuned : 99 — i34.4 ohms. 

Efficiency at resonance: — 11 db vs ideal. 


PRESSURE AT1 METER IN DB VS 1 DYNE /SO CM 
PER WATT AVAILABLE POWER FROM 135 OHMS 


SONAR EQUIPMENTS 


109 



180 “ 

Figure 115. Directivity pattern, CBM 78145 
projector at 24.2 kc. Directivity index = — 22.9 
db. 


















1 








1 



... 

i::;: 









V 





















1 10 100 


FREQUENCY IN KC 

Figure 116. Transmitting response, CBM 78145 
projector including junction box. Water temper- 
ature = 72 F. 



Figure 117. Receiving response, CBM 78145 
projector including junction box. Water temper- 
ature = 72 F. Calculated threshold at 24.2 kc 
= — 94 db vs 1 dyne/sq cm. 


Q 


CONFIDENTIAL 



110 


U. S. NAVY SONAR EQUIPMENTS 


2.7.28 QCS-1 Sonar-Ranging Projector (CBM 78164A) 

Type: Combination Magnetostriction and Rochelle Salt Crystal. 

Manufacturer : Submarine Signal Company, Type No. 900E. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: This projector is a combination of two units in one housing, 
one unit being used for echo ranging on distant objects and for telegraphic 
communication with other vessels similarly equipped and a second unit 
for listening to propeller noise or other machinery noise on moving vessels. 
It forms a major unit in the QCS-1 equipments for large A/S ships. 

Description: The CBM 78164A projector is banjo-shaped, 17 in. in 
diameter by 7% in. deep. One face is the diaphragm of the magnetostriction 
unit for echo ranging, and the opposite face is the diaphragm of the 
Rochelle salt listening unit. The projector is used inside a retractable free- 
flooding type dome (882A). 

The magnetostriction unit consists of a group of nickel tubes attached at 
one end to the steel plate serving as the diaphragm. The tubes are polarized 
by a d-c fleld and vibrate under the influence of a 24-kc alternating fleld 
supplied by the driver for transmitting acoustic pulses into the water. The 
unit functions also as a receiver to convert acoustic echoes into electric 
energy. The unit is parallel-split for BDI operation. 

The Rochelle salt listening unit consists of a number of blocks of X-cut 
Rochelle salt crystals fastened to a steel backing plate. The cavity between 
the crystals and the diaphragm is fllled with air-free castor oil. 

The CBM 78164A (900E) projector is similar to the CBM 78165A 
(900D) projector used in the QCT-1 equipments, except that the M/S 
unit of the latter operates at 20 kc instead of 24 kc. When these types of 
projectors are not split for BDI operation, they are known as the CBM 
78164 (900A) and the CBM 78165 (900) projectors. Weight of projector: 
250 lb. 

Efficiency: M/S unit at resonance: —13 db vs ideal. 

R/S unit (24 kc) : — 5 db vs ideal. 


SONAR EQUIPMENTS 


111 



90* 


I80‘ 


180' 


Figure 118. Directivity pattern, CBM 78164A 
projector at 24.2 kc. M/S unit. Connected parallel 
aiding. Directivity index = — 23 db. 


Figure 119. Directivity patterns, CBM 78164A 
projector. R/S unit. Directivity index: at 20 kc 
— 21.1 db, at 24 kc = — 23.8 db, at 28 kc 
= —25.2 db. 



i8(r 


Figure 120. BDI patterns, CBM 78164A pro- 
jector at 24.2 kc. M/S unit. Electrical phase shift 
= 67.5°. 



112 


U. S. NAVY SONAR EQUIPMENTS 




Figure 121. Transmitting response, CBM 
78164A projector. M/S unit. Connected parallel 
aiding. Water temperature = 62 F. Q = 45. 


Figure 122. Transmitting response, CBM 
78164A projector. R/S unit. Water temperature 
= 62 F. 


So -80 

> o 
— to 

to uj "90 

V : 

0)0 

zj -100 

W o 

h -1 

g UJ -110 

1 ^ 

i III] 


,-j 1 










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> t 

b “ 

ii -120 
S'" 

-130 

O U. 






























V 






































































1 

i 



1 











10 100 

FREQUENCY IN KC 


Figure 123. Receiving response, CBM 78164A 
projector. M/S unit. Connected parallel aiding. 
Water temperature = 62 F. Q = 36. Calculated 
threshold at 24.2 kc =: — 93.5 db vs 1 dyne/sq cm. 


o 

> o 
— w 


U.-70 
o 

a 

y -80 


HOO- 


r 


to 


f 


A 


\ 


FREQUENCY IN KC 


100 


Figure 124. Receiving response, CBM 78164A 
projector. R/S unit. Water temperature = 62 F. 
Calculated threshold at 24 kc = — 120.5 db vs 
1 dyne/sq cm. 



SONAR EQUIPMENTS 


113 



Figure 125. Impedance, CBM 78164A projector. 
M/S unit. 



Figure 126. Impedance, CBM 78164A projector. 
R/S unit. 


114 


U. S. NAVY SONAR EQUIPMENTS 


90 


^ QCU Sonar-Ranging Projector (CRV 78225) 

Type: Magnetostriction. 

Designer and Manufacturer : RCA Victor Division of the Radio Corpora- 
tion of America, Type No. MI 16740. 

Reference: NDRC Report No. 6.1-srll30-1379, April 28, 1944.®® 

Application: This projector is a part of the QCU echo-ranging equip- 
ment for medium-sized A/S ships. 

Description: The CRV 78225 projector is a magnetostriction unit with 
permanent-magnet polarization. It is approximately 14 in. in diameter. 
The active elements consist of 182 nickel tubes equally spaced in an equi- 
lateral triangle arrangement. The tubes have a length equivalent to one- 
quarter wavelength at the operating frequency, which is about 25 kc. The 
nickel tubes have one end imbedded in a circular steel plate % in. thick 
which serves as the diaphragm. The diaphragm is bolted to the metal 
housing over a Corprene gasket. The metal housing is lined outside with a 
cork, and a coating of neoprene extends over the housing and diaphragm. 

Electrical connection to the projector is provided by a series-parallel 
arrangement of 182 identical coils, with one coil over each nickel tube. The 
projector is a three-wire unit with the windings series-split for BDI 
operation. 

Impedance at resonance (25.4 kc) : 33.8 + ill7 ohms. 

Efficiency at resonance : — 3.8 db vs ideal. 


0 * 



Figure 127. Directivity pattern, CRV 78225 
projector at 25.5 kc. Connected series aiding. 
Directivity index = — 22.4 db. 



Figure 128. BDI patterns, CRV 78225 projector 
at 25.5 kc. Electrical phase shift = 70®. 


< i coNF iDExfiaaa 

^ ' 


SONAR EQUIPMENTS 


115 




Figure 129. Transmitting response, CRV 78225 
projector. Connected series aiding. Water temper- 
ature = 73 F. Q = 70. 


Figure 130. Receiving response, CRV 78225 
projector. Connected series aiding. Water temper- 
ature = 73 F. Q = 70. Calculated threshold at 
25.5 kc = — 99 db vs 1 dyne/sq cm. 



Figure 131B. CRV 78225 projector, component 
parts. 


Figure 131A. CRV 78225 projector. 



NICKEL] 

tubes) 


[DIAPHRAGM 


FLUX / 
[DISTRIBUTING 


[COIL “ 

Iassemi 


PLATE 


[PERMANENT 
I MAGNET 


[PERMANEI 

[MAGNET 




I.StfA 




NEIDENTIAL 


TV. 



116 


U. S. NAVY SONAR EQUIPMENTS 


QGA Sonar-Ranging Projector (CBM 78220) 

Type: Magnetostriction. 

Manufacturer : Submarine Signal Company, Type No. 941. 

Reference: NDRC Report No. 6.1-srll30-1626, June 7, 1944.^^ 
Application: The CBM 78220 projector is a major unit in the QGA equip- 
ment for echo ranging on large destroyers. This projector is the lower one 
of two tandem units vertically mounted in a fixed 100-in. dome. The upper 
unit, CBM 78221 (942), is tillable to permit ranging in a vertical direction. 

Description: This unit is a magnetostrictive type with permanent-magnet 
polarization. The active elements are nickel tubes with one end imbedded 
in a heavy steel plate diaphragm. The nickel tube and diaphragm are tuned 
to resonate at approximately 15 kc. The coil structure consists of a series- 
parallel arrangement of identical coils surrounding each tube. The pro- 
jector is parallel-split for BDI operation. 

Efficiency at resonance: — 7.5 db vs ideal. 



Figure 132. Directivity patterns, CBM 78220 
projector. Solid line: 1 w available power at 14.8 
kc. Directivity index = — 18.7 db. Broken line: 
400 w input power at 14.74 kc. Directivity index 
= —18.8 db. 



Figure 133. BDI patterns, CBM 78220 projector 
at 14.8 kc. Electrical phase shift = 60°. 



SONAR EQUIPMENTS 


117 





FREQUENCY IN KC 


Figure 134. Transmitting response, CBM 78220 
projector. Water temperature = 52 F. Q = 36. 



Figure 136. Impedance, CBM 78220 projector. 



FREQUENCY IN KC 

Figure 135. Receiving response, CBM 78220 
projector. Water temperature = 52 F. Q = 40. 
Calculated threshold at 14.8 kc = — 99 db vs 1 
dyne/sq cm. 



^pNFTOEXXIAL^ 


118 


U. S. NAVY SONAR EQUIPMENTS 


QGA Sonar-Ranging Projector (CBM 78221) 

Type: Magnetostriction. 

Manufacturer : Submarine Signal Company, Type No. 942. 

Reference: NDRC Report No. 6.1-srll30-1626, June 7, 1944.^^ 

Application: The CBM 78221 projector is a major unit in the QGA 
equipment for echo ranging on large destroyers. This projector is the 
upper one of two tandem units vertically mounted in a fixed 100-in. dome. 
This unit is tiltable to permit ranging in a vertical direction. The lower 
unit, CBM 78220 (941), is a low-frequency (15 kc) unit for long distance 
ranging. 

Description: This unit is a magnetostrictive type with permanent-magnet 
polarization. The active elements are nickel tubes with one end imbedded 
in a steel plate diaphragm. The nickel tubes and diaphragm are mechani- 
cally tuned to resonate at approximately 30 kc. The coil structure consists 
of a series-parallel arrangement of identical coils, one of which surrounds 
each tube. The projector is parallel-split for BDI operation. 

Efficiency at resonance: — 7.5 db vs ideal. 



Figure 138. Directivity patterns, CBM 78221 
projector. Solid line: 1 w available power at 
30.56 kc. Directivity index = — 23.2 db. Broken 
line: 400 w input power at 30.49 kc. Directivity 
index = — 23.4 db. 



Figure 139. BDI patterns, CBM 78221 pro- 
jector at 30.47 kc. Electrical phase shift = 60°. 


SONAR EQUIPMENTS 


119 



Figure 140. Transmitting response, CBM 78221 
projector. Water temperature 80 F. Q = 25.8. 


Figure 142. Impedance, CBM 78221 projector. 



Figure 141. Receiving response, CBM 78221 
projector. Water temperature = 80 F. Q = 25.2. 
Calculated threshold at 30.5 kc = — 98 db vs 1 
dyne/sq cm. 


I 




120 


U. S. NAVY SONAR EQUIPMENTS 


QGB Sonar-Ranging Projector (CRV 78210) 


Type: Magnetostriction. 

Manufacturer: RCA Victor Division of the Radio Corporation of 
America, Type No. MI 16727-3. 

Reference: NDRC Report No. 6.1-srll30-1985, January 16, 1945.'^2 

Application: This projector is normally used in the QGB sonar ranging 
equipment for large A/S ships mounted in a retractable-type dome. This 
unit is arranged for BDI operation. 

Description: The CRV 78210 projector is a magnetostriction unit with 
permanent magnet polarization. Series-split connections to the two halves 
of the projector are provided for BDI operation. The projector is designed 
to operate from a transmitting source of 100 ohms at 400 w electric 
power input. 

Four types of the QGB projector, differing only in frequency of reso- 
nance, are supplied. These types are designated as: 


Frequency 
20 kc 
22 kc 
24 kc 
26 kc 


V. S. Navy No. 
CRV 78208 
CRV 78209 
CRV 78210 
CRV 78211 


Mfg. No. 
MI 16727-4 
MI 16727-1 
MI 16727-3 
MI 16727-2 


Equipment 

QGB 

QGB 

QGB 

QGB 


Efficiency: CRV 78210 projector at resonance: — 6.6 db vs ideal. 



Figure 144. Directivity pattern, CRV 78210 Figure 145. BDI patterns, CRV 78210 projector 

projector at 24.5 kc. Directivity index — 23.6 at 24.5 kc. Electrical phase shift = 81.8°. 

db. 




SONAR EQUIPMENTS 


121 



Figure 146. Transmitting response, CRV 78210 
projector. Water temperature = 66 F. Q = 70. 




Figure 149A. CRV 78210 projector. 


Figure 147. Receiving response, CRV 78210 
projector. Water temperature = 66 F. Q. = 77. 
Calculated threshold at 24.5 kc = — 101 db vs 
1 dyne/sq cm. 



FREQUENCY IN KC 



IIAPHRA6M 


COVER- 


PERMANENT 

MAGNETS^ 


NICKEL 

TUBES 


FLUX • 
DISTRI8UTII 

PLATE.-.- >' 


.OIL -J 
SEMBL^ 


Figure 149B. CRV 78210 projector, component 
parts. 


Figure 148. Impedance, CRV 78210 projector. 


CONFIDENTIAL 





122 


U. S. NAVY SONAR EQUIPMENTS 


2.7.33 


QJB Sonar-Ranging Projector (CW 78207) 


Type: ADP Crystal. 

Designer: Bell Telephone Laboratories. 

Manufacturer : Western Electric Company, Type No. D-166471. 

Reference: NDRC Report No. 6.1-srll30-1986, January 16, 1945.'^^ 

Application: This CW 78207 unit is used as the projector in QBE and 
in QJA echo-ranging equipments for ranging on objects at distances up 
to 10,000 yd. The CW 78207 and the CW 78178 projectors are inter- 
changeable. 

Description: The CW 78207 projector is similar to the CW 78178, 
except that the active elements in the CW 78207 unit consist of ADP 
crystals instead of Y-cut Rochelle salt crystals. In external appearance 
it is identical with the QBE (CW 78178) projector. 

Efficiency at 24 kc: — 4.0 db vs ideal. 



SONAR EQUIPMENTS 


123 



Figure 150. Directivity pattern, CW 78207 pro- 
jector at 24 kc. Connected parallel aiding. Di- 
rectivity index = — 22.6 db. 




8 ° 


o o 
> u. 


-70 

-80 

-90 

100 

-110 

-120 




I 


10 


FREQUENCY IN KC 


100 


Figure 152. Receiving response, CW 78207 pro- 
jector. Connected parallel aiding. Water temper- 
ature = 60 F. Calculated threshold at 24 kc = 
— 101.8 db vs 1 dyne/sq cm. 




Figure 151. Transmitting response, CW 78207 

projector. Connected parallel aiding. Water Figure 153. Impedance, CW 78207 projector, 

temperature = 60 F. Connected parallel aiding. 


CONFIDENTIAI^r 


REACTANCE 



124 


U. S. NAVY SONAR EQUIPMENTS 


2.7.34 WCA-1 Sonar-Ranging Projector (CBM 78153) 

Type: Combination Magnetostriction and Rochelle Salt Crystal. 

Manufacturer: Submarine Signal Company, Type No. 733H. 

Reference: USRL Orlando Project No. 137, January 1945. 

Application: The CBM 78153 projector consists of a magnetostriction 
(QC) unit and a Rochelle salt (JK) unit in a spherical housing. It is one 
of three projectors used in the WCA and WCA-1 equipments for sub- 
marines. These two equipments diifer only in the voltage of the d-c power 
supply. The CBM 78153 projector is mounted on the port side of the ship. 
The magnetostriction or QC unit of this projector is used for echo ranging 
at 24 kc, and the Rochelle salt or JK unit is used for supersonic listening. 
A second QB-type Rochelle salt crystal projector, CBM 78154 (733J), 
is mounted on the starboard side of the ship and may be used for echo 
ranging at any frequency in the range 14 to 32 kc. A third projector, CBM 
78155 (763J), is mounted on the bottom of the hull and is used for depth 
sounding at 24 kc. The ranging equipment can be used for telegraphic 
communication between vessels similarly equipped. 

Description: The CBM 78153 combination projector consists of a 
magnetostriction unit and a Rochelle salt unit mounted back to back on a 
common frame. With hemispherical covers the projector is spherical in 
shape and 19 in. in diameter. 

The M/S unit consists of a group of nickel tubes firmly imbedded in a 
steel diaphragm. The nickel tubes and diaphragm are designed to resonate 
at about 24 kc. Each tube is surrounded by a coil through which flows the 
d-c polarizing current and the pulses of 24 kc supplied by the driver. A 
total polarizing current of approximately 7.5 amp is required. The unit 
is not arranged for BDI. A hemispherical stainless steel shell is fastened 
over the diaphragm and the cavity is filled with a 50 per cent mixture of 
ethylene glycol and water. 

The R/S unit has a number of X-cut Rochelle salt crystals mounted on a 
steel backing plate. The opposite faces of the crystals are in one plane and 
form the sound receiving surface. A hemispherical rubber shell encloses 
the crystals, and the cavity between the crystals and the shell is filled 
with air-free castor oil. 

Impedance: M/S unit at resonance: 93 + ^148 ohms. 

R/S unit at 24 kc: 45 — yil3 ohms. 

Efficiency: M/S unit at resonance: — 13.0 db vs ideal. 

R/S unit at 24 kc: — 2.0 db vs ideal. 



SONAR EQUIPMENTS 


125 



Figure 154. Directivity pattern, CBM 78153 pro- 
jector at 24.22 kc. M/S unit. Directivity index = 
—20.7 db. 



Figure 156. Transmitting response, CBM 78153 
projector. M/S unit. Water temperature = 63 F. 
Q = 54. 



Figure 155. Directivity patterns, CBM 78153 
projector. R/S unit. Directivity index: at 20 kc 
= —22.2 db, at 24 kc =: —23.2 db, at 28 kc 
= —24.8 db. 



Figure 157. Transmitting response, CBM 78153 
projector. R/S unit. Water temperature = 61 F. 


ONFIDENTIAL 


J 





OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF I DYNE/SQ CM 


126 


U. S. NAVY SONAR EQUIPMENTS 



Figure 158. Receiving response, CBM 78153 
projector. M/S unit. Water temperature = 63 F. 
Q = 44. Calculated threshold at 24.22 kc = 91.5 
db vs 1 dyne/sq cm. 



Figure 159. Receiving response, CBM 78153 
projector. R/S unit. Water temperature = 61 F. 
Calculated threshold at 24 kc = — 106 db vs 1 
dyne/sq cm. 



Figure 160. Impedance, CBM 78153 projector. 
R/S unit. 




NFroENTIAL 



SONAR EQUIPMENTS 


127 


2.7.35 WCA-2 WEB Sonar-Ranging Projector (CBM 78212) 

Type: Combination Magnetostriction and Rochelle Salt Crystal. 

Designer and Manufacturer : Submarine Signal Company, Type No. 948. 

Reference: USRL Orlando Project No. 137, January 1945. ' 

Application: The CBM 78212 projector, consisting of a magnetostric- 
tion unit and a Rochelle salt unit in one housing, is used for echo ranging, 
telegraphic communication, and for listening in the WCA-2 and WEB 
equipments for submarines. This projector is used in combination with 
the CBM 78214 sounding projector in the WEB equipment and in com- 
bination with the CBM 78213 R/S echo-ranging projector and the CBM 
78214 sounding projector in the WCA-2 equipment. 

Description: The CBM 78212 projector is a combination magnetostric- 
tion unit and a Rochelle salt unit in a spherical housing. The diameter is 
approximately 19 in. 

The magnetostriction echo-ranging unit consists of a group of nickel 
tubes which are attached at one end to the circular steel plate serving 
as the diaphragm. The nickel tubes and diaphragm are tuned to resonate 
at approximately 24 kc. The coil structure consists of a series-parallel 
arrangement of identical coils, with one coil surrounding each tube. The 
coils carry the 24-kc driving current. The unit contains a permanent 
magnet and is parallel-split for BDI operation. The diaphragm is cov- 
ered by a hemispherical shell of stainless steel. The space between the 
diaphragm and cover is free-flooded. 

The Rochelle salt listening unit consists of a group of X-cut Rochelle 
salt crystal blocks mounted on a steel backing plate. The crystals are en- 
closed by a hemispherical rubber cover, and the space between the crystals 
and cover is filled with air-free castor oil. 

Efficiency: M/S unit at resonance: — 10.0 db vs ideal. 

R/S unit at 24 kc: — 2.1 db vs ideal. 


PRESSURE ATI METER IN DB VS 1 DYNE/SQ CM 
PER WATT AVAILABLE POWER FROM 100 OHMS 


128 


U. S. NAVY SONAR EQUIPMENTS 





Figure 161. Directivity pattern, CBM 78212 
projector at 23.55 kc. M/S unit. Connected 
parallel aiding. Directivity index = — 21.2 db. 



Figure 163. Transmitting response, CBM 78212 
projector. M/S unit. Connected parallel aiding. 
Water temperature = 61 F. Q = 35. 



Figure 162. Directivity patterns, CBM 78212 
projector. R/S unit. Directivity index: at 20 kc 
= —22.2 db, at 24 kc = —23.5 db, at 28 kc 
= —24.8 db. 



Figure 164. Transmitting response, CBM 78212 
projector. R/S unit. Water temperature = 62 F. 


^ ffl^FIDENTIAi;|l 


SONAR EQUIPMENTS 


129 



Figure 165. Receiving response, CBM 78212 
projector. M/S unit. Connected parallel aiding. 
Water temperature = 61 F. Q = 31. Calculated 
threshold at 23.55 kc = — 95.5 db vs 1 dyne/sq cm. 



Figure 166. Receiving response, CBM 78212 
projector. R/S unit. Water temperature = 62 F. 
Calculated threshold at 24 kc = — 105 db vs 1 
dyne/sq cm. 



Figure 167. Impedance, CBM 78212 projector. 
M/S unit. 



R/S unit. 


( CONTIDEyri^ 



130 


U. S. NAVY SONAR EQUIPMENTS 


2.7.36 WCA-2 Sonar-Ranging Projector (CBM 78213) 

Type: 45° X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Submarine Signal Company, Type No. 
733R. 

Reference: NDRC Report No. 6.1-srll30-1820, August 11, 1944.®^ 

Application: The CBM 78213 projector is used for ranging and listening 
in the WCA-2 equipment. Its function is to enable the operator to listen 
to and determine the bearing of high-frequency sound generated by the 
propellers or other moving parts of a distant vessel. In the WCA-2 equip- 
ment this projector is used in combination with the CBM 78212 projector 
for echo ranging and telegraphic communication with other vessels 
similarly equipped, and with the CBM 78214 projector for echo sounding. 

Description: This projector has 45° X-cut Rochelle salt crystals con- 
nected in parallel as its active elements. The crystal assembly is enclosed 
in a sphere of about 19 in. diameter, with the front hemisphere made of 
rubber. The space between the crystals and the front cover is filled with 
castor oil. The crystal assembly is split vertically for BDI operation. 

Efficiency at 24 kc : — 2.8 ±; 1 db vs ideal. 



SONAR EQUIPMENTS 


131 


0 * 



180 * 


Figure 169. Directivity pattern, CBM 78213 
projector at 24 kc. Directivity index = — 24.2 db. 



Figure 171. Receiving response, CBM 78213 
projector. Water temperature = 64 F. Calculated 
threshold at 24 kc = — 106 db vs 1 dyne/sq cm. 



Figure 170. Transmitting response, CBM 78213 
projector. Water temperature = 64 F. 



Figure 172. Impedance, CBM 78213 projector. 




ONFIDENTIAL 


REACTANCE —OHMS 





132 


U. S. NAVY SONAR EQUIPMENTS 


2.7.37 WEA-1 Sonar-Ranging Projector (CRV 78151) 

Type: Magnetostriction. 

Manufacturer : RCA Victor Division of the Radio Corporation of Amer- 
ica, Type No. MI 8992. 

Reference: NDRC Report No. 6.1-sr20-607, February 25, 1943.^^ 
NDRC Report No. 6.1-sr20-951, August 24, 1943.®® 

NDRC Report No. 6.1-sr20-954, September 2, 1943.^^ 
NDRC Report No. 6.1-sr20-959, October 15, 1943.^1 

Application: The CRV 78151 projector is used in the WEA-1 sonar 
equipment for small A/S ships for echo ranging and listening only. The 
45° baffle, originally installed in the WEA-1 dome to permit the same 
projector to be used for depth sounding, has been removed. Recent units 
incorporate a Corprene band to reduce rear response, and the windings 
are split for BDI. 

Description: The CRV 78151 projector is a permanent-magnet magneto- 
strictive type in a banjo-shaped housing approximately 9 in. in diameter. 
The active element consists of a group of nickel tubes with one end im- 
bedded in the circular steel plate serving as the diaphragm. The coil 
assembly consists of a series-parallel arrangement of identical coils, one 
coil surrounding each tube. These coils carry the pulses of 24-kc driving 
current. 

Efficiency at resonance: — 6.5 db vs ideal. 



OPEN CIRCUIT VOLTS IN OB VS I VOLT PRESSURE ATI METER IN DB VS 1 DYNE/SO CM 

FOR A SOUND FIELD OF 1 DYNE /SO CM PER WATT AVAILABLE POWER FROM 135 OHMS 


SONAR EQUIPMENTS 


133 



[i'lGURE 174. Transmitting response, CRV 78151 
Drojector. Water temperature = 69 F. Q = 75. 




Figure 177A. CRV 78151 projector. 


Figure 175. Receiving response, CRV 78151 
projector. Water temperature = 69 F. Q = 80. 
Calculated threshold at 24.6 kc = — 97 db vs 1 
dyne/sq cm. 



FREQUENCY IN KC 

Figure 176. Impedance, CRV 78151 projector. 



Figure 177B. CRV 78151 projector, component 
parts. 




NFIDEN 


134 


U. S. NAVY SONAR EQUIPMENTS 


2.7.38 WEA-2 Sonar-Ranging Projector (CBM 78156) 

Type: Combination Magnetostriction and Rochelle Salt Crystal. 

Designer and Manufacturer : Submarine Signal Company, Type No. 885. 

Reference: NDRC Report No. C4-sr20-295, November 16, 1942.^® 

Application: The CBM 78156 projector is a major unit in the WEA-2 
equipment for ranging, listening, and sounding on small A/S vessels. 
Sounding is accomplished in this equipment with the projector in combina- 
tion with a 45° baffle in the tail section of the WEA-2 torpedo-shaped 
dome to direct the acoustic pulses downward. 

Description: The CBM 78156 projector is a combination magnetostric- 
tion and Rochelle salt crystal unit in a banjo-shaped housing 14 in. in 
diameter. The magnetostriction, or QC, face has an effective diameter of 
about I2V2 in. at its normal operating frequency of 24 kc. It requires a 
polarizing current of 3 amp. The recommended maximum a-c input voltage 
is 200 V. The d-c resistance of the windings is about 20 ohms. 

The crystal, or JK, face of the projector has an effective diameter of 
about 11 in. The recommended maximum input voltage is 100 v, 100 w, 
and for intermittent use 145 v, 145 w. 

Impedance at 24 kc: M/S unit: 382 -f ^451 ohms. 

R/S unit: 55.3 — yi8.6 ohms. 

Efficiency at 24 kc: M/S unit: — 11.5 db vs ideal. 

R/S unit: — 3 db vs ideal. 


NFIDENTIAL - 


SONAR EQUIPMENTS 


135 



180 * 


Figure 178. Directivity pattern, CBM 78156 
projector at 23.95 kc. M/S unit. Directivity index 
—24.2 db. 



Figure 179. Directivity pattern, CBM 78156 
projector at 23.95 kc. R/S unit. Directivity index 
= —23.8 db. 



Figure 180. Transmitting response, CBM 78156 
projector. M/S unit. Water temperature = 72 F. 
Q = 60. 



Figure 181. Transmitting response, CBM 78156 
projector. R/S unit. Water temperature = 68 F. 



Figure 182. Receiving response, CBM 78156 
projector. R/S unit. Water temperature = 60 F. 
Calculated threshold at 23.95 kc = — 107.5 db vs 
1 dyne/sq cm. 


^yc oNFroENfiA^i^ 



136 


U. S. NAVY SONAR EQUIPMENTS 


BTL QB-Type ADP Projector 
Type: ADP Crystal. 

Designer and Manufacturer: Bell Telephone Laboratories. 

Reference: NDRC Report No. 6.1-srll30-2131, February 1, 1945.'® 
Application: The QB-type ADP crystal projector was produced as an 
engineering model to serve as the bottom-side unit in the WFA-1 sonar 
equipment for submarines. The unit is intended for use both as an echo- 
ranging and as a listening transducer at supersonic frequencies. 

Description: This projector is a modification of and is similar in external 
appearance to the 19-in. spherical QB-type projector. The active elements 
in this unit are ADP crystals. This projector is a four-wire unit split 
electrically for BDI or PAL operation. 

Efficiency at 25 kc : — 3.5 db vs ideal. 



PRESSURE AT 1 METER IN DB VS 1 OYNE/SQ CM 
PER WATT AVAILABLE POWER FROM 135 OHMS 


SONAR EQUIPMENTS 


137 



Figure 183. Directivity patterns, BTL QB-type 
ADP projector. Directivity index: at 20 kc = 
— 22.4 db, at 25 kc = — 24.1 db, at 30 kc == — 25.6 
db. 



Figure 185. Receiving response, BTL QB-type 
ADP projector. Connected parallel aiding. Water 
temperature = 61 F. Calculated threshold at 25 
kc = — 105 db vs 1 dyne/sq cm. 



Figure 184. Transmitting response, BTL QB- 
type ADP projector. Connected parallel aiding. 
Water temperature = 61 F. 



Figure 186. Impedance, BTL QB-type ADP 
projector. 



REACTANCE IN OHMS 



138 


U. S. NAVY SONAR EQUIPMENTS 


Brush 14-Inch ADP Crystal Projector AX-63 

Type: ADP Crystal. 

Designer and Manufacturer: Brush Development Company. 

Reference: NDRC Report No. 6.1-srll30-1187, November 16, 1943.®^ 

Application: The AX-63 is one of the first experimental-type echo- 
ranging units making use of ADP crystals in place of Rochelle salt crystals. 

Description: The AX-63 projector consists of a number of ADP crystals 
in a cylindrical housing 14 in. in diameter and approximately 5 in. deep. 
The diaphragm face of the projector is rubber-covered. A i/ 2 -in. thick 
Corprene covering is placed over the back of the projector to reduce 
rear response. 

Figures showing characteristics of AX-63 projector are included in 
Section 7.6.4. 

Impedance at 24.2 kc : 202 — ^963 ohms. 

Efficiency: — 2 db vs ideal. 


, ^ ^FIDENTIA ^ 



140 


U. S. NAVY SONAR EQUIPMENTS 


NRL ADP Projector X-5 


Type: ADP Crystal. 

Designer: Naval Research Laboratory. 

Reference: NDRC Report No. 6.1-srll30-1988, January 25, 

Application: The X-5 projector is an experimental model embracing a 
modification of the QB-JK type 19-in. spherical projector. The active 
elements are ADP crystals instead of x-cut Rochelle salt crystals as used 
in the JK projector. 

Description: The active elements of the X-5 projector consist of %-in. 
wide strips of ADP crystals mounted on a steel plate. Fifty of these strips 
are mounted on each half of the diaphragm, and the two halves are 
separated by a cork strip. Electric connections are brought out from 
each half of the projector separately to adapt it for BDI. The projector is 
mounted in a standard JK spherical housing. The hemispherical window 
is made of sound-transparent rubber 1 in. thick, and the space behind is 
filled with air-free castor oil. 

Efficiency at 24 kc: — 2.4 db vs ideal. 



90* 


Figure 187. Directivity patterns, NRL ADP 
projector X-5. Directivity index at 24 kc = — 20 
db. 


SONAR EQUIPMENTS 


141 



1 10 100 
FREQUENCY IN KC 


Figure 188. Transmitting response, NRL ADP 
projector X-5. Connected parallel aiding. Water 
temperature = 37 F. 



Figure 190. Impedance, NRL ADP projector 
X-5. Connected parallel aiding. 



Figure 189. Receiving response, NRL ADP pro- 
jector X-5. Connected parallel aiding. Water 
temperature = 37 F. Calculated threshold at 24 
kc = — 103 db vs 1 dyne/sq cm. 



FRONT VIEW 

Figure 191. NRL ADP projector X-5. 


REACTANCE IN OHMS 


142 


U. S. NAVY SONAR EQUIPMENTS 


NRL ADP Projector X-6 


Type: ADP Crystal. 

Designer: Naval Research Laboratory. 

Reference: NDRC Report No. 6.1-srll30-1988, January 25, 

Application: The X-6 projector is an experimental model embracing a 
modification of the QB-JK type 19-in. spherical projector. The active 
elements are ADP crystals instead of the Rochelle salt crystals as used 
in the JK projector. 

Description: The X-6 projector employs a number of crystal blocks 
mounted individually on a bakelite backplate by means of brass studs. 
Two types of crystal blocks are used, one type consisting of eight ll^xlxV8 
in. crystals, the other type being made up of sixteen 11 / 4 x 1 / 2 x 1 /^ in. crystals. 
A total of 92 crystal blocks are used in the projector. The projector unit 
is mounted in a standard JK housing and is split for BDI operation. 

Efficiency at 24 kc : — 9.6 db vs ideal. 


JONFIDENTL 


PRESSURE ATI METER IN DB VS 1 OYNE/SO CM 
PER WATT AVAILABLE POWER FROM 135 OHMS 


SONAR EQUIPMENTS 


143 


0 “ 



180 * 


Figure 192. Directivity patterns, NRL ADP 
projector X-6. Directivity index at 24 kc = — 24.3 
db. 



Figure 194. Receiving response, NRL ADP pro- 
jector X-6. Connected parallel aiding. Water 
temperature = 37 F. Calculated threshold at 24 
kc = — 99 db vs 1 dyne/sq cm. 



FREQUENCY IN KC 


o 

-100 


-200 


-•300 


-400 


-500 


Figure 195. Impedance, NRL ADP projector 
X-6. Connected parallel aiding. 



Figure 193. Transmitting response, NRL ADP 
projector X-6. Connected parallel aiding. Water 
temperature = 37 F. 



Figure 196. NRL ADP projector X-6. 



REACTANCE-OHMS 


144 


U. S. NAVY SONAR EQUIPMENTS 


RCA ADP Crystal Projector 

Type: ADP Crystal. 

Manufacturer : RCA Victor Division of the Radio Corporation of Amer- 
ica. 

Reference: NDRC Report No. 6.1-srll30-1985, January 16, 1945.’^2 

Application: This ADP projector is designed for use in sonar-ranging 
equipment. It is arranged for BDI operation. This projector is similar 
to the Brush Development Company AX-102-1 projector. 

Description: The active elements of this projector are ADP crystals. 
The crystals are arranged in two diametrically opposite groups with 
separate electric connections to each group. Parallel-split connections to 
the two halves of the projector are provided for BDI operation. The pro- 
jector is designed to operate from a transmitting source of 100 ohms at 
100 w electric power input. 

Efficiency at 22.3 kc: — 1.2 db vs ideal. 




90 * 


Figure 197. Directivity pattern, RCA ADP 
crystal projector at 22.3 kc. Directivity index = 
—20.4 db. 


Figure 198. BDI patterns, RCA ADP crystal 
projector at 22.3 kc. Electrical phase shift = 
74.3“. 





SONAR EQUIPMENTS 


145 



Figure 199. Transmitting response, RCA ADP 
crystal projector. Water temperature = 64 F. 
Q = 4.0. 



Figure 201. Impedance, RCA ADP crystal pro- 
jector. 



Figure 200. Receiving response, RCA ADP 
crystal projector. Water temperature = 64 F. 
Q — 4.5. Calculated threshold at 22.3 kc = — 104 
db vs 1 dyne/sq cm. 



Figure 202. RCA ADP crystal projector. 



REACTANCE— OHMS 


146 


U. S. NAVY SONAR EQUIPMENTS 


Submarine Signal QB-Type ADP Crystal Projector SK 5982 
Type: ADP Crystal. 

Designer and Manufacturer : Submarine Signal Company. 

Reference: NDRC Report No. 6.1-srll30-1191, December 15, 1943.®^ 
Application: This projector is an experimental unit designed for echo 
ranging and listening at supersonic frequencies. 

Description: The SK 5982 projector is similar to the JK spherical pro- 
jector except that ADP crystals are used instead of Rochelle salt crystals. 
The unit is split vertically for BDI operation. 

Efficiency at 30 kc : — 4.0 db vs ideal. 


'ONFIDENTIAL f 


SONAR EQUIPMENTS 


147 



Figure 203. Directivity patterns, Submarine 
Signal QB-type ADP crystal projector SK 5982. 
Directivity index at 24 kc = — 24.8 db, at 30 kc 
= —26.1 db. 



Figure 205. Receiving response, Submarine 
Signal QB-type ADP crystal projector SK 5982. 
Connected parallel aiding. Water temperature = 
48 F. Calculated threshold at 30 kc = — 97 db vs 
1 dyne/sq cm. 



Figure 204. Transmitting response. Submarine 
Signal QB-type ADP crystal projector SK 5982. 
Connected parallel aiding. Water temperature 
= 48 F. 



Figure 206. Impedance, Submarine Signal QB- 
type ADP crystal projector SK 5982. Connected 
parallel aiding. 


CSONFIDENTIALIj; 



148 


U. S. NAVY SONAR EQUIPMENTS 


‘‘Football-Type” WFA-1 Topside Transducer 

Type: ADP Crystal. 

Designer and Manufacturer: Bell Telephone Laboratories, Type No. 
D171307. 

Reference: NDRC Report No. 6.1-srll30-2295, June 25, 

Application: The 'Tootball-type'' transducer was produced as an engi- 
neering model to serve as the topside unit in the WFA-1 sonar equipment 
for submarines. The unit is intended for both echo ranging and listening 
at supersonic frequencies and for listening in the sonic range. 

Description: The active elements of this transducer consist of ADP 
crystals. The transducer is made up of separate sections. The sonic 
listening elements are twenty-four 1x1x1. 1 in. crystals encased in a 
cylindrical metal housing. These crystals are tuned by the mass and stiff- 
ness of the end plates of the cylindrical housing. 

The section of the transducer designed for echo ranging and listening 
at supersonic frequencies consists of a group of crystal blocks each 0.5x 
0.5x0.66 in. mounted on a steel plate. The crystals in this group are tuned 
by resonators which are an integral part of the mounting plate. Separate 
electric connections are provided to the middle two horizontal rows of 
crystals in this group. These crystals comprise the maintenance of close 
contact [MCC] section. This grouping is designed to produce a broad 
vertical beam pattern and a sharp horizontal beam pattern. 

All groups of crystals may be connected in parallel for listening in the 
sonic range. The two halves of all sections of the transducer are brought 
out separately to make them adaptable for use in BDI or in PAL circuits. 

The crystal assembly is protected by a rubber diaphragm. The free 
space between the diaphragm and the crystals is vacuum-filled with oil. 
Weight of complete assembly: 1,000 lb. 

Efficiency: Hydrophone (H) section at 6 kc: — 27 db vs ideal. 

Plate (P) section at 24 kc: — 5 db vs ideal. 

MCC section at 24 kc: — 5.5 db vs ideal. 

Entire Unit (S) at 6 kc: — 22.5 db vs ideal. 


FIDENTIAL 


I 


SONAR EQUIPMENTS 


149 



180 “ 


Figure 207. Directivity pattern, football-type 
WFA-1 topside transducer. Entire unit S at 6 kc. 
Directivity index — 18.5 db. 



Figure 208. Directivity pattern, football-type 
WFA-1 topside transducer. Listening unit H at 
6 kc. Directivity index = — 20.0 db. 



Figure 209. Directivity pattern, football-type 
WFA-1 topside transducer. Plate unit P at 24 
kc. Directivity index = — 21.5 db. 



180 “ 

Figure 210. Directivity pattern, football-type 
WFA-1 topside transducer. Center unit MCC at 
24 kc. Directivity index — — 15.0 db. 


['^CONFIDENTIAL 


PRESSURE AT \ METER tN DB VS I DYNE /SO CM 
PER WATT AVAILABLE POWER FROM 135 OHMS 


150 


U. S. NAVY SONAR EQUIPMENTS 



Figure 211. Transmitting response, football- 
type WFA-1 topside transducer. Water tempera- 
ture = 60 F. 



Figure 212. Receiving response, football-type 
WFA-1 topside transducer. Water temperature 
= 60 F. Calculated threshold: entire unit S at 6 
kc = — 92 db vs 1 dyne/sq cm, listening unit H 
at 6 kc = — 91 db vs 1 dyne/sq cm, plate unit P 
at 24 kc = — 98 db vs 1 dyne/sq cm, center unit 
MCC at 24 kc = — 92 db vs 1 dyne/sq cm. 



Figure 213. Impedance, football-type WFA-1 
topside transducer. 




SONAR EQUIPMENTS 


151 



Figure 214. Football-type WFA-1 topside trans- 
ducer. 


Figure 215. Football-type WFA-1 topside trans- 
ducer with rubber cover removed. 


CONFIE 




152 


U. S. NAVY SONAR EQUIPMENTS 


90 ' 


2.7.46 Harvard Sword Arm Depth Angle Transducer 

Type: Magnetostriction. 

Designer: Harvard University Underwater Sound Laboratory. 

Reference: NDRC Report No. 6.1-srll30-1826, August 28, 1944.'^^ 

Application: This transducer is an experimental unit intended for use 
in determining the range and depth of underwater objects such as sub- 
marines. 

Description: The sword arm depth angle transducer consists of 32 per- 
manent-magnet polarized stacks of annealed nickel mounted in a bronze 
casting. The laminated stacks are Cycle-Welded to the rubber nosepiece. 
The transducer is intended to be mounted vertically, and the housing is 
streamlined. Shading to reduce the height of the side lobes is accom- 
plished by the number of turns of wire on the stacks, those stacks located 
near the middle of the transducer having more turns than the stacks 
located farther away. The transducer is split for BDI operation. 

Efficiency: — 4.7 db vs ideal. 



Figure 216. Directivity patterns, Harvard 
sword arm depth angle transducer at 60 kc. 



Figure 217. BDI patterns, Harvard sword arm 
depth angle transducer at 60 kc. Electrical phase 
shift = 60°. 




SONAR EQUIPMENTS 


153 



Figure 218. Transmitting response, Harvard 
sword arm depth angle transducer. Connected 
parallel aiding. Q = 11.5. Water temperature = 
68 F. 



Figure 219. Receiving response, Harvard sword 
arm depth angle transducer. Connected parallel 
aiding. Water temperature = 68 F. Q = 11.5. 
Calculated threshold at 60 kc = — 89 db vs 1 
dyne/sq cm. 



Figure 220. Impedance, Harvard sword arm 
depth angle transducer. Connected parallel 
aiding. 



LAYOUT OF LAMINATED NICKEL STACKS SHOWING 
TOTAL NUMBER OF TURNS OF WIRE ON EACH STACK 


SINTERED 
OXIDE MAGNETX 



ACTIVE FACE 


WINDINGS CUSHIONED 
WITH AIR-CELL NEOPRENE 

100 LAMINATIONS OF .005 
ANNEALED NICKEL CONSOLIDATED 
WITH 55-6 CYCLEWELD RESIN 


Figure 221. Harvard sword arm depth angle 
transducer. 


STAINLESS STEEL SHEET . 



Figure 222. Permanent magnet polarized stack 
for Harvard sword arm transducer. 


154 


U. S. NAVY SONAR EQUIPMENTS 


HP-4 Laminated Stack Transducer 
Type: Magnetostriction. 

Designer: Harvard University Underwater Sound Laboratory. 
Reference: NDRC Report No. 6.1-srll30-1826, August 28, 1944.'^^ 
Application: The HP-4 transducer is an experimental unit. 
Description: The HP-4 transducer consists of a consolidated stack of 
annealed laminations with permanent, sintered oxide magnet. The lamina- 
tions are Cycle-Welded to the inside of a rectangular face 2%x3% in. A 
sheet-metal housing fits over the motor unit. The housing is lined with 
air-sealed neoprene, and a rubber sealing tape is employed to fasten the 
housing to the motor unit. 

Efficiency: — 4.7 db vs ideal. 



180 * 


Figure 223. Directivity patterns, HP-4 lami- 
nated stack transducer at 27 kc. Directivity 
index = — 9.8 db. 



Figure 224. Directivity patterns, HP-4 lami- 
nated stack transducer at 52.5 kc. 



SONAR EQUIPMENTS 


155 



68 F. 



2 ^ 


o 

24S 


o 

z 

20 < 


Figure 227. Impedance, HP-4 laminated stack 
transducer. 



Figure 226. Receiving response, HP-4 lami- 
nated stack transducer. Water temperature = 
68 F. Calculated threshold at 27 kc = — 89 db vs 
1 dyne/sq cm. 





156 


U. S. NAVY SONAR EQUIPMENTS 


Submarine Signal Projector SK 4044 

Ty'pe: Electrodynamic. 

Designer and Manufacturer : Submarine Signal Company. 

Reference: NDRC Report No. C4-sr20-202, September 3, 1942.^^ 

Application: The SK 4044 projector is an experimental-type echo-rang- 
ing projector. 

Description: The SK 4044 projector is an electrodynamic-type unit con- 
taining a permanent magnet. The diaphragm of this unit is 6 in. in 
diameter. Maximum allowable input power is 20 w. The projector is tuned 
to resonate at about 15 kc by means of condensers built into the unit. 

Impedance at 15 kc : 86.6 — yi9.8 ohms. 

Efficiency at 15 kc: — 9 db vs ideal. 


PRESSURE AT 1 METER IN DB VS 1 DYNE/SQ CM 
PER WATT AVAILABLE POWER FROM 135 OHMS 


SONAR EQUIPMENTS 


157 


0 “ 



180 “ 


Figure 229. Directivity pattern, Submarine 
Signal projector SK 4044 at 15 kc. Directivity 
index = — 13,3 db. 



Figure 230. Transmitting response, Submarine 
Signal projector SK 4044. Water temperature = 
90 F. Q = 20. 



Figure 231. Receiving response. Submarine 
Signal projector SK 4044. Water temperature = 
90 F. Q = 20. Calculated threshold at 15 kc = 
— 94 db vs 1 dyne/sq cm. 



-DRIVING 

RING 


Figure 232. Submarine Signal projector SK 
4044. 


CONFIDENTIA] 


158 


U. S. NAVY SONAR EQUIPMENTS 


Submarine Signal Projector SK 4610C 

Type: Magnetostriction. 

Designer and Manufacturer: Submarine Signal Company. 

Reference: NDRC Report No. C4-sr20-201, August 29, 1942.'^® 

Application: The SK 4610C is an experimental depth-sounding type pro- 
jector. 

Description: This projector is a laminated permanent-magnet type 
magnetostriction unit in a reflector-type housing. The calibration data for 
this projector is given for the unit tuned by means of a capacity of 
0.045 ixf in series with the projector winding. 

Impedance at 18.5 kc: 82 -f yiO ohms. 

Efficiency at 18.5 kc: — 8 db vs ideal. 



SONAR EQUIPMENTS 


159 



Figure 233. Directivity patterns, Submarine 
signal projector SK 4610C at 18.4 kc. Directivity 
index = — 20 db. 



Figure 234. Transmitting response, Submarine 
Signal projector SK 4610C. Water temperature 
= 80 F. 


WATER FILLER 
PLUGS TO HOUSING 



4-.065" GAL. PLATES 
OVER. I"SEALED CELL 
RUBBER AS 



Figure 235. Submarine Signal projector SK 
4610C. 


Chapter 3 

DOMES 


A GENERAL DISCUSSION of the use and the 
acoustic design of domes has been given.^ 
It will be recalled here that, in general, a 
streamlined dome is necessary for an echo- 
ranging or listening device in order to minimize 
the noise caused by its passage through the 
water, and the resultant turbulence and cavita- 
tion about its active face. The dome, of course, 
should be of optimum hydrodynamic shape; 
mechanically, it should have sufficient strength 
to resist pressure and drag, and should be 
constructed of a noncorrosive sea-resistant ma- 
terial. Finally, the dome should be acoustically 
transparent, causing as little disturbance as 
possible in the response and directivity of the 
enclosed acoustic device. 

To be acoustically transparent, the dome 
must fulfill the following two main require- 
ments. 

1. It must have a small transmission loss.’^ 
2. It must not introduce large specular re- 
flection side lobes into the directivity pattern 
of the enclosed transducer. 

In addition, the dome should not distort the 
enclosed transducer’s directivity pattern by 
multiple reflections, e.g., appreciably raise its 
rear response, nor should it appreciably alter 
the width of the transducer’s main lobe or in- 
crease the magnitude of the side lobes already 
present in the directivity pattern. Finally, in- 
ternal reflections from the dome should not 
greatly alter the transducer’s radiation imped- 
ance. All of these last effects are, however, quite 
small in modern, well-designed domes. 

The various acoustical disturbances intro- 
duced by domes, such as specular reflections 
and transmission losses, are, of course, inter- 
related. In general, a dome which introduces 
small specular reflections also causes small 
transmission losses. Moreover, because the 
change in the transducer’s radiation impedance 
is small, its total power output is unaffected by 

^ See STR Division 6, Volume 10, Chapter 9, and the 
references quoted therein. 

’^The transmission loss gives the reduction in the 
magnitude of the axis response of a transducer upon 
dome enclosure. 


enclosing it within a dome ; also, “true absorp- 
tion” of sound within the dome wall is negli- 
gible for metal domes. As a consequence, the 
energy which is removed by the dome wall 
from the impinging transducer beam, and 
which constitutes the transmission loss, is re- 
distributed in directions other than the original 
direction of incidence; in particular, the major 
portion of this energy is concentrated in the 
direction of specular reflection.'" This redistri- 
bution has the effect of increasing the value of 
the directivity index; it can be shown that:'* 

Transmission loss in db = db change in trans- 
ducer directivity index introduced by the dome. 

Expressions have been obtained theoretically, 
and generally verified experimentally, for the 
magnitudes of both the transmission loss and 
the specular reflection induced by a dome of 
given material, wall thickness, and dimensions 
on an enclosed transducer of given frequency, 
directivity, and position within the dome.'* 
These expressions indicate that the transmis- 
sion loss of a dome depends only on the thick- 
ness and density of the dome wall and on the 
frequency, increasing as any of these quantities 
increase. On the other hand, the specular re- 
flection, in addition to increasing with increas- 
ing dome-wall thickness and density and with 
the frequency, also depends on the horizontal 
and, particularly, the vertical curvature of the 
dome wall and on the directivity and location 
of the enclosed transducer. The specular re- 
flection is greatly minimized by increasing the 
vertical dome-wall curvature ; thus torpedo- 
shaped domes with a large vertical as well as 
a moderate horizontal curvature give much 
smaller specular reflections than straight-sided 
domes of the same wall thickness and density 
but possessing horizontal curvature only.® 

^ The magnitude of the additional side lobes intro- 
duced by the dome into the directivity pattern, e.g., the 
additional rear response, also increases as the trans- 
mission loss increases. 

^ See STR Division 6, Volume 10, Chapter 9. 

® See Table 1 and Figures 12 to 44; also STR Division 
6, Volume 10, Chapter 9. 


DOMES 


161 


Since both the transmission and specular re- 
flection decrease with the dome-wall thickness 
and density, dome design has tended to employ 
wall materials as thin and as light as possible, 
consistent with sufficient mechanical strength 
and general seaworthiness. Thus, while most 
dome walls or “acoustic windows’’ have thus 
far been constructed from corrosion-resisting 
steel, other materials, namely, aluminum, vari- 
ous plastics, and stiff rubber strengthened me- 
chanically by an expanded metal-grid struc- 
ture, have all been used experimentally.^ 

The first two of these materials are excellent 
acoustically; however, their seaworthiness is 
questionable. Although it is claimed that alu- 
minum corrodes , easily in sea water, proper 
treatment of the metal may render it salt- 
water resistant.®^ Plastics are subject to aging 
and temperature effects. Stiff rubber is acousti- 
cally but little inferior to standard 0.020-in. 
steel,® and is probably preferable from the 
standpoint of seaworthiness. 

In the attempt to achieve minimum dome- 
wall or acoustic window thickness consistent 
with mechanical strength, it has been found 
possible, in straight-sided domes at least, to use 
quite thin walls (0.020 in. to 0.030 in.) sup- 
ported by an expanded metal-grid structure.^ 
Such an arrangement is acoustically preferable 
to using thicker walls.®^ The acoustic window 
may also be reinforced by aluminum ribs (Brit- 
ish design, see Figure 10), or corrugated sheet 
construction may be used. The latter® has the 
additional virtue of decreasing the magnitude 
of the specular reflection (though not of the 
transmission loss) to values smaller than those 
obtained with a noncorrugated wall of the same 
thickness.^^ Finally, torpedo domes, because of 
their shape, have greater mechanical strength 
for a given thickness than straight-sided domes. 

Table 1 refers to representative domes at 
present in use in the U. S. Navy for housing 
echo-ranging projectors, as well as to several 
experimental models. The domes are classified 
according to shape, longest dimension, wall 
(acoustic window) material and thickness, type 

^ The rubber is vulcanized to both sides of the grid 
structure. 

8 See Table 1. 

^ See Figures 2 and 3 for photographs showing the 
grid structure. 


of filling, and mode of suspension. The acoustic 
properties of the domes obtained from USRL 
calibrations, and summarized in terms of their 
transmission loss and specular reflection at 
specified angles and frequencies, are also given. 

It is seen that the transmission loss, which 
depends only on the wall thickness and density 
and on the frequency, is in general small, par- 
ticularly for the 0.020-in. to 0.030-in. domes. 
Specular reflection, which depends on the wall 
thickness, wall material, and frequency, is also 
strongly affected by the horizontal and, par- 
ticularly, vertical curvature of the walls. The 
torpedo-shaped, vertically-curved domes, even 
though equipped with walls much thicker than 
the acoustic windows of the straight-sided 
domes (for example, QBF : 0.020 in., vs QCU-1 : 
0.050 in.) have, nevertheless, comparable and 
often smaller specular reflections. The numeri- 
cal values of the transmission loss and specular 
reflection of all these domes are in general 
agreement with theoretical expectations." 

Figures 1 to 11 are photographs and di- 
agrams of several representative and most 
widely used domes listed in Table 1 (photo- 
graphs of QGA, QBF, QCU-1; diagrams of 
QGA, QBF, British, WEA-1, QCU-1, QC 
spherical). These photographs and diagrams 
show details of the mechanical construction and 
layout of the domes, for example, acoustic 
window wall, expanded metal-grid structure, 
position of reinforcing ribs, position of pro- 
jector and baffle.^ Explanatory captions are 
included. 

Figures 12 to 44 show directivity patterns 
of the bare projector and of the enclosed pro- 
jectors with 0, 30, 45, and 60 degrees between 
the projector and dome axes. Patterns are 
given for the QCU-1, QCU-2, and WEA-1 tor- 
pedo-shaped, and the QBF, 54-in., and QGA 
straight-sided domes. The patterns are obtained 
by keeping the angle between projector and 
dome axis fixed, and rotating both simultane- 

^ See STR Division 6, Volume 10, Chapter 9. 

i The baffles used in domes to shield the projector 
from propeller noise (see STR Division 6, Volume 10, 
Chapter 9) are shown in Figures 2 and 3 for the QBF 
and QGA domes. These baffles consist of a reflecting 
steel plate (^ ^/4 in. thick) facing the screws attached 
to a wire mesh castor oil absorbing assembly (^ 3 in. 
thick), with a front rubber cover acting to absorb any 
stray sound from the dome nose. 


"CONFIDENTIAlf 


162 


DOMES 


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* Where several reports are quoted, measurements on the same dome with transducers of similar directivity are all averaged together. 

t The rather high specular reflection in this case is due not only to the large wall thickness (0.062 in.), but also to the excessively wide beam of the projector employed. 


DOMES 


163 


ously relative to a fixed sound source. These 
patterns show the magnitude of the specular 
reflections’" and of other disturbances intro- 
duced by the various domes into the directivity 
pattern. The other disturbances involve multiple 
reflections, increase in rear response, broaden- 
ing of the main lobe, etc. ; they are compara- 
tively small in practically all cases. 

Figures 45 to 47 show transmission loss 
versus frequency curves taken at 0° between 
dome and projector axes for representative 
straight-sided and torpedo domes (QGA, QBF, 
and QCU-2). It is seen that the transmission 
loss in general increases with frequency. 

Figures 48 and 49 show transmission loss 

^ The values of the specular reflections included in 
Table 1 are obtained from these patterns. It may be 
noted that the specular reflections usually occur at 
angles with respect to the dome axis which are expected 
from the value of angle of incidence; the latter is 
determined by the angle between the dome and pro- 
jector axes and by the geometry of the dome.^^ 


versus orientation of projector relative to dome 
axis, i.e., for different angles of sound incidence 
for the straight-sided QBF and the torpedo- 
shaped WEA-1 domes. It is seen that the trans- 
mission loss is practically independent of the 
angle of incidence, at least within the range 
used, i.e., up to angles of 45°. Theory and ex- 
periment both indicate, however, that the 
transmission loss becomes larger at higher fre- 
quencies and oblique angles of incidence, i.e., 
angles greater or equal to 75°.’ The large losses 
exhibited in the diagrams at angles ^ 180° be- 
tween dome and projector axes are due to the 
effect of the shielding baffle within the dome. 


1 Thus the comparatively large transmission loss of 
the corrugated dome is due to sound incident obliquely 
on part of the corrugation. Further, in Figure 47 for 
the transmission loss of the QCU-2 dome, the curve 
referring to the projector tilted through 75° (large 
angle of incidence on dome wall) exhibits the large loss 
at the higher frequencies. 


1 1 ALTj 


164 


DOMES 


Figure 1. QCU dome, Navy type No. CUB- 
78223. Figure 3. 100-in. QGA dome, Navy type No. 

CUB-78201, top view. 





Figure 2. View of QBF dome. 


BAFTLE 


?>OUND • 
T^ANSPA 
WINOOW 



Figure 4. 100-in. QGA dome. Navy type No. 

CUB-78201, forward view. 


DOMES 


165 



ACCESS PLATE 


FREE ROOOING HO 


SOUND 


WINDOW 


DRAIN PLUG 


I sctial!-^ 

FlATt I ^ 


Figure 5. 100-in. QGA dome, Navy type No. 

CUB-78201, starboard view. 



l8i‘'DIA 

■4 



Figure 6. QC spherical dome. 




BAFFLE 

Figure 8. WEA-1 torpedo-shaped dome. 


PROJECTOR 


SERIAL NO. STAMPED HERE 

\ 16" 


SKIN 1/8" 
CORROSION 
RESISTING 
STEEL 


REFLECTOR PAD 



NAVY TYPE NUMBER 


'.020" CORROSION 
RESISTING STEEL 


EXPANDED METAL 

BAFFLE_/ BACKING 

Figure 9. 50-in. QBF straight-sided dome. 


.PROJECTOR 


18 


SKIN. 020’* 
CORROSION 
RESISTING 
STEEL 


REINFORCING RIBS 





f 








* n w 

t( itMn 

t 

1 



_ir 




, Te NICKEL 
CAST IRON 


• BOLT 

SOUND 

TRANSPARENT 

WINDOW 


BOTTOM 5/16" 
NICKEL CAST IRON 



'DRAIN PLUG 


Figure 10. 54-in. British type straight-sided 

dome. 


►NFIDENTIA 



166 


DOMES 



0 * 



180 * 

Figure 12. Receiving directivity pattern, QCU 
No. 5 projector at 25.38 kc without dome. Other 
patterns for this unit and frequency in Figures 
13-15. 



Figure 13. Receiving directivity pattern: in 
QCU-1 dome with baffle. Unit at 0° with respect 
to dome axis. Projector and dome rotated to- 
gether. 


0 * 



in QCU-1 dome with baffle, in QCU-1 dome 

without baffle. Unit at 30° with respect to dome 
axis. Projector and dome rotated together. 


DOMES 


167 


0 * 



180 * 


Figure 15. Receiving directivity pattern : 

in QCU-1 dome with baffle, in QCU-1 dome 

without baffle. Unit at 45° with respect to dome 
axis. Projector and dome rotated together. 






10 1] 

njs 


\\i 

V A— X 

20-i^ 

'V' \ < 

v\\ \ ^ 

XLiV/ 


Figure 16. Receiving directivity pattern, 14-in. 
RCA ADP crystal projector at 25 kc. Projector 
alone. Other patterns for this unit and frequency 
in Figures 17-19. 



90 * 


Figure 17. Receiving directivity pattern : in 70- 
in. QCU-2 torpedo dome. Bearing angle 0°. Dome 
and projector rotated together. 



90 * 


Figure 18. Receiving directivity pattern : in 70- 
in. QCU-2 torpedo dome. Bearing angle 30°. Dome 
and projector rotated together. 


lENtlXL' '?! 



168 


DOMES 



Figure 19. Receiving directivity pattern : in 70- 
in. QCU-2 torpedo dome. Bearing angle 45°. Dome 
and projector rotated together. 


0 “ 



Figure 20. Receiving directivity pattern, 
WEA-1 projector at 24.5 kc without dome. Other 
patterns for this unit and frequency in Figures 
21-29. 

f 



Figure 21. Receiving directivity pattern : in 20- 
mil stainless steel WEA-1 dome. Unit at 0° with 
respect to dome axis. Projector and dome rotated 
together. 


0 * 



180 ® 


Figure 22. Receiving directivity pattern : in 20- 
mil stainless steel WEA-1 dome. Unit at 30° with 
respect to dome axis. Projector and dome rotated 
together. 



DOMES 


169 



Figure 23. Receiving directivity pattern: in 20- 
mil stainless steel WEA-1 dome. Unit at 60° with 
respect to dome axis. Projector and dome rotated 
together. 



Figure 25. Receiving directivity pattern: in 30- 
mil stainless steel WEA-1 dome. Unit at 30° with 
respect to dome axis. Projector and dome rotated 
together. 



Figure 24. Receiving directivity pattern: in 30- 
mil stainless steel WEA-1 dome. Unit at 0° with 
respect to dome axis. Projector and dome rotated 
together. 


90“ 



~~rT^F7Z 7 






90“ 


Figure 26. Receiving directivity pattern : in 30- 
mil stainless steel WEA-1 dome. Unit at 60° with 
respect to dome axis. Projector and dome rotated 
together. 





170 


DOMES 


0 * 



180 “ 


Figure 27. Receiving directivity pattern : in 38- 
mil aluminum WEA-1 dome. Unit at 0° with 
respect to dome axis. Projector and dome rotated 
together. 


0 “ 



Figure 28. Directivity pattern : in 38-mil alumi- 
num WEA-1 dome. Unit at 30° with respect to 
dome axis. Projector and dome rotated together. 


90 “ 



Figure 29. Receiving directivity pattern: in 38- 
mil aluminum WEA-1 dome. Unit at 60° with 
respect to dome axis. Projector and dome rotated 
together. 


0 “ 



180 “ 


Figure 30. Receiving directivity pattern, BTL 
projector QBF No. 461 at 24 kc without dome. 
Other patterns for this unit and frequency in 
Figures 31-33. 



DOMES 


171 


0 “ 



QBF dome. Projector at 0° with respect to dome 
axis. Projector and dome rotated together. 



QBF dome. Projector at 30° with respect to dome 
axis. Projector and dome rotated together. 


90 » 



90° 


Figure 33. Receiving directivity pattern: in 
QBF dome. Projector at 45° with respect to dome 
axis. Projector and dome rotated together. 


0 ° 



180° 


Figure 34. Receiving directivity pattern, XQB- 
6S projector at 25 kc without dome. Other 
patterns for this unit and frequency in Figures 
35-37. 



172 


DOMES 



Figure 35. Receiving directivity pattern : in 30- 
mil 54-in. dome No. 892. Projector at 0° with 
respect to dome axis. Projector and dome rotated 
together. 



180 ® 

Figure 36. Receiving directivity pattern: in 30- 
mil 54-in. dome No. 892. Projector at 45° with 
respect to dome axis. Projector and dome rotated 
together. 



Figure 37. Receiving directivity pattern, QGA 
transducer 94111A at 14.72 kc without dome. 
Other patterns for this unit and frequency in 
Figures 38-40. 


0 ® 



180 ® 


Figure 38. Receiving directivity pattern : in 
100-in. QGA dome. Transducer at 30° with respect 
to dome axis. Transducer and dome rotated to- 
gether. 


6^fidenti 


DOMES 


173 




90 * 


180 “ 

Figure 41. Receiving directivity pattern, QGA 
transducer 94211A at 30.47 kc without dome. 
Other patterns for this unit and frequency in 
Figures 42-44. 

0^ 


Figure 42. Receiving directivity pattern: in 
100-in. QGA dome. Transducer at 0° with respect 
to dome axis. Transducer and dome rotated to- 
gether. 


90 “ 


Figure 39. Receiving directivity pattern : in 
100-in. QGA dome. Transducer at 30° with re- 
spect to dome axis. Transducer and dome rotated 
together. 

0 “ 


Figure 40. Receiving directivity pattern: in 
100-in. QGA dome. Transducer at 45° with respect 
to dome axis. Transducer and dome rotated to- 
gether. 


NFIDEKTTALi 







174 


DOMES 


0* 



Figure 43, Receiving directivity pattern : in 
100-in. QGA dome. Transducer at 30° with respect 
to dome axis. Transducer and dome rotated to- 
gether. 



100-in. QGA dome. Transducer at 45° with re- 
spect to dome axis. Transducer and dome rotated 
together. 





















~1 









































2 













EOF 

ETIi 

3 AL 





d 

1 

































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1 



















































































0 10 20 30 40 50 60 70 80 90 100 

FREQUENCY IM KC 


Figure 45. Transmission loss of 100-in. QGA 
dome versus frequency. 



Figure 46. Transmission loss of QBF dome 
versus frequency. 






































































/ 

7* 















- 

f 








1 

PRi 

75 

OJ 

O 

EC 

D 

01 

01 

Vll 

R TILTED 

AT 


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I 1 

PROJE 

:cTo 

R ; 

XT 

O' 

» 













DOME AT 0“ , 

1 1 i t 1 1 




m 

o 

^6 

<n 

CO 


92 

CO 

CO 

s 

^0 


Figure 47. Transmission loss of QCU-2 torpedo 
dome versus frequency. 


GONFirTENTLAL;. 




DOMES 


175 



Figure 48. Measured attenuation of QBF pro- 
jector response due to QBF dome. Used as a 
hydrophone at 24 kc. Dome rotated. Unit fixed at 
0° with reference to sound source. 



Figure 49. Measured attenuation of WEA-1 
projector response due to 38-mil aluminum dome. 
Used as a hydrophone at 24.5 kc. Dome rotated. 
Unit fixed at 0° with reference to sound source. 


CONFIDENTIAL 


1 


Chapter 4 

BRITISH AND CANADIAN EQUIPMENT 


* 1 ASDIC AND HYDROPHONE UNITS 

T he equipment described in this chapter in- 
cludes four Asdic units and five hydro- 
phones. Asdic®® is the term used to designate 
any British or Canadian sonar equipment hav- 
ing both listening and echo-ranging features, 
although some gear used for listening only 
have been called Asdic. The Asdics described 
herein are both echo-ranging and listening de- 
vices. They have been designed for practically 
every class of ship, and various frequencies 
are used so that ships operating in a group do 


not suffer from mutual interference. 

The original Asdic oscillator consisted of a 
quartz steel sandwich tuned by the thickness 
of the steel plates, as in the Asdic Oscillator 
A/S 96. Now Rochelle salt crystals and ADP 
crystals are also used, as well as magnetostric- 
tive coupling, e.g.. Asdic Set, Type 135 and 
Asdic Transducer, Type 150. Tourmaline is 
used in special hydrophones, e.g., HT-1, and 
quartz is used in others, e.g.. Type P, Quartz 
Crystal Low-Frequency Standard. Forty-five 
degree X-cut Rochelle salt crystals are used in 
the Canadian B1 and FI hydrophones. 


176 




V 




178 


BRITISH AND CANADIAN EQUIPMENT 


Asdic Oscillator A/S 96 

Type: Quartz Crystals between Steel Plates. 

Reference: NDRC Report No. 6.1-sr20-608, March 4, 1943.^^^ 

Use: Echo ranging. 

Description: The Asdic Oscillator A/S 96 (equivalent to A/S 95), Pat- 
tern No. 1200, consists of disk quartz between steel face plates. The reso- 
nance of the oscillator is determined by the thickness of the steel face 
plates in conjunction with the stiffness of the quartz disks. The oscillator 
frequency is designated by the suffix letter in the serial number, Y indi- 
cating 14 kc; A, 15 kc; B, 16 kc; C, 17 kc, etc. The unit illustrated resonated 
at about 15 kc. 

For transmitting, the oscillator is supplied from a circuit having a 
resistance of 52 ohms and an inductance of about 17 mh. For reception 
the oscillator is connected across a high Q coil having an inductance of 
18 mh. A trimmer condenser connected across the oscillator terminals 
is used for fine adjustment of the frequency of resonance of the unit. 

Efficiency at resonance: — 3 db vs ideal. 



90 * 


Figure 1. Directivity pattern. Asdic oscillator 
A/S 96 at 14.94 kc. Directivity index == — 22.0 db. 



ASDIC AND HYDROPHONE UNITS 


179 


o o 


— cc 


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o ^ 

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FREQUENCY IN KC 

Figure 2. Transmitting response, Asdic oscil- 
lator A/S 96. Water temperature = 64 F. 



Figure 4. Impedance, Asdic oscillator A/S 96. 



Figure 3. Receiving response. Asdic oscillator 
A/S 96. Water temperature = 64 F. Q = 40. 
Calculated threshold at 14.94 kc = — 103 db vs 
1 dyne per sq cm. 


LIFTING PLATE 


INTERPLATE 


QUARTZ DISK 




I 





y' 




■FACE PLATE 


Figure 5. Asdic oscillator A/S 96. 


Wxg .IDEXnATM 


REACTANCE IN OHMS 


180 


BRITISH AND CANADIAN EQUIPMENT 


Asdic Set, Type 135 


Type: Magnetostriction. 

Reference: NDRC Report No. 6.1-srll30-1827, September 4, 1944.^^^ 

Use: Locating small objects. 

Description: The Asdic Set, Type 135 uses two identical magnetostric- 
tion transducers, one for transmitting pulses of damped sinusoidal oscilla- 
tions produced by a condenser discharge, the other for receiving incoming 
acoustic echoes. The active element of the transducer consists of a stack 
of annular nickel laminations 5 in. in diameter by 2% in. high. Around 
this stack is a toroidal winding of 24 turns of insulated wire. A surge of 
current through this winding will cause the stack to contract. Restoring 
forces will then cause the stack to oscillate at the resonant frequency, 
about 15 kc. To obtain a directional response each unit is mounted in a 
double-walled, air-hlled, parabolic reflector. The transmitting unit is 
normally polarized by the d-c component of the condenser-discharge input. 
The receiving unit is polarized by the residual magnetism from a large 
current flowing through the winding for a very short time. 

Other essential units in the Asdic Set, Type 135 are a recorder unit, 
a contractor unit, and an amplifier-rectifier unit. The recorder unit con- 
sists of a chemical recorder, a cam operating a transmitter switch, and a 
second cam operating the time- varied gain [TVG] feature in the receiving 
amplifier. The function of the transmitter switch is to energize the con- 
tactor which charges a condenser and discharges it through the 
transmitting unit. Incoming acoustic signals are converted to electric 
energy in the receiving unit and passed through the amplifier-rectifier 
unit to the chemical recorder through the pen stylus which sweeps across 
the paper from left to right. The TVG of the amplifier-rectifier unit is 
obtained by changing the grid bias exponentially by means of a con- 
denser discharge. The instant at which the condenser begins discharging 
is controlled by the switch in the recorder unit. 

A “subtraction circuit,’’ not shown in the schematic, is used to smooth 
out the reverberation background and thus allow the recorder trace to 
stand out more sharply on the record. This subtraction circuit is basically 
a network for insertion between the output of the amplifier-rectifier and 
the recorder to remove the d-c components from the signal. 

Efficiency: receiving unit: — 14.5 db vs ideal. 

transmitting unit : — 14.3 db vs ideal. 

Peak sound pressure in generated acoustic pulse : 1.16 X 10^ dynes per 
sq cm. 

Amplification of tuned circuit and amplifier: approximately 100 db at 
15 kc. 


, ^ONFIDENTIAlil 


ASDIC AND HYDROPHONE UNITS 


181 


90' 




90* 


180* 


Figure 6. Directivity pattern, receiving unit 
Asdic set, Type 135, at 15.4 kc. Directivity index 
= —18.9 db. 


180' 


Figure 7. Directivity pattern, transmitting unit 
Asdic set. Type 135, at 14.9 kc. Directivity index 
= —19.6 db. 



180* 


Figure 8. Directivity pattern, receiving unit of 
Asdic set. Type 135, for peak pressure of con- 
denser-discharge pulse. Transmitted by A/S 135 
transmitting unit. 


/a 


CONFIDENTIAL 


3 



182 


BRITISH AND CANADIAN EQUIPMENT 



Figure 9. Transmitting response, Asdic set, 
Type 135. Q = 12. 



Figure 11. Impedance, Asdic set. Type 135. 



Figure 10. Receiving response. Asdic set. Type 
135. Q = 12. Calculated threshold: receiving 
unit at 15.4 = — 93 db vs 1 dyne per sq cm; 
transmitting unit at 14.9 kc = — 95 db vs 1 dyne 
per sq cm. 



Figure 12. Simplified circuit schematic. Asdic 
set. Type 135. 


RZACTANCE IN OHMS 


ASDIC AND HYDROPHONE UNITS 


183 



Figure 13. Asdic set, Type 135 oscillator. 


'V CONFI DENTIAL ^ 


184 


BRITISH AND CANADIAN EQUIPMENT 


^ Asdic Transducer, Type 150 

Type: Magnetostriction. 

Reference: NDRC Report No. 6.1-srll30-2136, February 17, 1945.^^^ 

Use: Locating small objects. 

Description: The Asdic Transducer, Type 150 is a magnetostrictive type 
similar in many respects to the Type 135 transducer. The active element 
consists of a stack of annular nickel laminations on which is a toroidal 
winding of insulated wire. Each stack is about IV 2 in. high and 5 in. in 
diameter. Two of the units are mounted one behind the other in a single 
parabolic reflector enclosed in a spherical shell approximately 12 in. in 
diameter. The shell is filled with water. One magnetostrictive element 
serves as the shock-excited transmitter while the other is used as the 
receiver. The electric circuit used with the Type 150 transducer is essen- 
tially the same as is used in the Asdic Set, Type 135. The transmitting 
unit is normally polarized by the d-c component of the condenser-discharge 
input. The receiving unit is polarized by the residual magnetization pro- 
duced by a large current which flows through the winding for a very short 
time. 

Efficiency: receiving unit: — 15 db vs ideal. 

transmitting unit: — 19 db vs ideal. 



Figure 14. Directivity pattern, receiving unit 
Asdic transducer, Type 150, at 13.8 kc. Directivity 
index = — 19.5 db. 



90 * 


ISO* 


Figure 15. Directivity pattern, transmitting 
unit Asdic transducer. Type 150, at 14.1 kc. Di- 
rectivity index = — 19.5 db. 


^ I confidentiaU 



ASDIC AND HYDROPHONE UNITS 


185 



1 10 too 


FREQUENCY IN KC 

Figure 16. Transmitting response, Asdic trans- 
ducer, Type 150. Water temperature 60 F. 



Figure 18. Impedance, Asdic transducer, Type 
150. 



Figure 17. Receiving response, receiving unit 
Asdic transducer. Type 150. Water temperature 
= 60 F. Calculated threshold at 13.8 kc = — 93 
db vs 1 dyne per sq cm. 



r CONFIDENTIAL 


REACTANCE IN OHMS 


186 


BRITISH AND CANADIAN EQUIPMENT 


4 . 1.4 


HT-1 Hydrophone 


Type: Tourmaline Crystal. 

Reference: NDRC Report No. 6.1-sr20-952, August 30, 1943.2®^ 

Use: Underwater sound measurements. 

Description: The transducer element consists of two rectangular tour- 
maline disks, % in. by 2 mm, which have been dipped in Aquadag to 
provide an electrical shield for the head. The head is then dipped in 
Vulcalox to protect the head and Aquadag layer. The hydrophone was 
tested with a one-stage preamplifier mounted in a standard Cll-Al 
housing, as shown in the drawing. The preamplifier is terminated by a 
29-ft rubber-covered cable. 



OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF 1 DYNE /SO CM 


ASDIC AND HYDROPHONE UNITS 


187 






111 



















i ! 

1 



















j 1 

i 




















































































1 





























o 

160 V 



0®. 






































1 




■~1 



















hr- 






















s 



/ 

/ 



















1/ 





















i 




O.t 1 10 100 


FREQUENCY IN KC 

Figure 20. Receiving response, HT-1 hydro- 
phone. 



Figure 21. Calculated threshold, HT-1 hydro- 
phone. 




Figure 22. HT-1 hydrophone and preamplifier 
circuit. 


COJmDENTIAU 


1 


188 


BRITISH AND CANADIAN EQUIPMENT 


4 . 1.5 


Type P Hydrophone 


Type: Quartz Crystal. 

Reference: USRL Mountain Lakes Project No. 281B, June 5, 1944. 

Use: Underwater sound measurement. 

Description: The capacity of the quartz head is approximately 100 
but it is shunted by about 1,000 It is associated with a two-stage 
preamplifier of the cathode-follower type, using a British H63 tube in 
the first stage and a 6J5 in the second stage. The grid resistor of the 
H63 is 50 megohms, but 1,000 megohms is used when the instrument is 
used at low frequencies. 



OPEN CIRCUIT VOLTS IN 
00 VS 1 VOLT FOR A SOUND 
lain in 08 FIELD OF I DYNE /SO CM 


ASDIC AND HYDROPHONE UNITS 


189 



Figure 23. Receiving response and pream- 
plifier gain, Type P hydrophone. 



Figure 24. Measured threshold, Type P hydro- 
phone. 



Figure 25. Type P hydrophone. 


^,co>a miEyfiAL -J 



190 


BRITISH AND CANADIAN EQUIPMENT 


Quartz Crystal Low-Frequency Standard 

Type: Quartz Crystal. 

References: NDRC Report No. 6.1-sr20-619, May 6, 1943.^® 

NDRC Report No. 6.1-sr20-879, June 19, 1943.^^ 

NDRC Report No. 6.1-srll30-1364, February 4, 1944.^^® 
NDRC Report No. 6.1-srll30-1623, May 24, 1944.^®® 

Use: Hydrophone standard. 

Description: This device is similar to the Quartz Crystal Hydrophones 
No. 34 and No. 24. It uses a two-stage preamplifier of the cathode-follower 
type employing an H63 and L63 vacuum tube (see preamplifier circuit). 

The hydrophone has two rubber-covered active faces. The crystal ele- 
ment is housed in a heavy bronze casting of 6-in. outside diameter. The 
associated preamplifier is contained in a casting to which the hydrophone 
is attached by a watertight connection. 


* ^imDENTIA|) - 


OPEN CIRCUIT VOLTS IN OB VS 1 VOLT 
FOR A SOUND FIELD OF I DYNE /SO CM 


ASDIC AND HYDROPHONE UNITS 


191 


*IA JA 



Figure 27. Preamplifier circuit, quartz crystal 
low-frequency standard. 



Figure 26. Receiving response, quartz crystal 
low-frequency standard. 



ard. 


CONFIDENTIAL 




VOLTAGE ACROSS 600 OHMS IN DB VS 1 VOLT 


192 


BRITISH AND CANADIAN EQUIPMENT 


^ Canadian NRE B1 Hydrophone 

Type: 45° X-Cut Rochelle Salt Crystal. 

Manufacturer : Naval Research Establishment of Canada. 

Reference: USRL calibration letter of July 10, 1945, to Naval Research 
Establishment. 

Use: Underwater sound measurement. 

Description: The B1 hydrophone is similar to the XMX hydrophone but 
is designed on a smaller scale. It is made up of four 0.035-in. thick, 45° 
X-cut Rochelle salt crystals in parallel. Other dimensions of crystals are 
approximately l^x%6 in. 




Figure 29. Receiving response, NRE B1 hydro- Figure 30. Measured threshold, NRE B1 hydro- 
phone. Water temperature = 68 F. phone. 


; ' i I 'i ‘ ^ ' 

( jCOXFIDENTIAL^ 


ASDIC AND HYDROPHONE UNITS 


193 


Canadian NRE FI Hydrophone 

Type: 45° X-Cut Rochelle Salt Crystal. 

Manufacturer: Naval Research Establishment of Canada. 

Reference: USRL calibration letter of July 10, 1945, to Naval Research 
Establishment. 

Use: Underwater sound measurement. 

Description: The 45° X-cut Rochelle salt crystal bank in the FI hydro- 
phone is the same as for the XMX hydrophone. The crystal bank is mounted 
in a bakelite holder % in. in diameter by % in. thick. 













I I 


































/' 




A 







-P 











r 




I I 

— 

— < 






r 


::F° 

0 

1 











— ISO* 

























I I 












■+9pJ'T' 








— 




-SO-T' 

— 








^ !!* 

hf- 


T 












t 


0.1 1 10 100 


frequency in kc 


Figure 31. Receiving response, NRE FI hydro- 
phone. Water temperature = 68 F. 



Figure 33. Measured threshold, NRE FI hydro- 
phone. 




100 1000 icpoo 

FREQUENCY IN KC 

Figure 32. High-frequency receiving response, 

NRE FI hydrophone. Water temperature = 68 F. Figure 34. NRE FI hydrophone. 





Chapter 5 

NAVAL LABORATORIES’ DESIGNS 


SUMMARY 

O NE OF THE PRIMARY objectives of the USRL 
was to assist the Navy and the various 
naval laboratories in their work on underwater 
sound equipment. A large proportion of the cali- 
bration work done by USRL was concerned 
with devices submitted by the Naval Research 
Laboratory [NRL], the Naval Ordnance Labo- 
ratory [NOL], the David Taylor Model Basin, 
the USS SemmeSf the U. S. Naval Mine War- 
fare Test Station at Solomons, Maryland, the 
Bureau of Ships, and the Bureau of Ordnance. 
In addition, the Signal Corps General Develop- 
ment Laboratory, which at the beginning of 
the war was responsible for harbor defense, 
has had calibration work done by the USRL. 

Much of the equipment of commercial com- 
panies such as Western Electric Company, 
Radio Corporation of America, and Submarine 
Signal Company is based on development work 
done by these agencies. The information as to 
how much of the responsibility for design was 
theirs is not available to the USRL in many 
cases, and, consequently, the devices in this re- 
port are credited to the manufacturer. 

Much sonar equipment designed by NRL is 
in use by the Navy and is described in Chapter 
2. The NRL also has developed a number of 
experimental units, such as the X-5 and X-6 
projectors, also covered in Chapter 2. In addi- 
tion, they have developed a number of hydro- 
phone standards such as the OLA, which was 
adopted by the USRL as one of their standards 


(see Chapter 1), and a low-frequency NRL 
design, the K type, which was used by the U. S. 
Naval Mine Warfare Test Station and is de- 
scribed in Section 5.1.1. 

The USRL calibrated various hydrophones 
for NOL, including a number of secret devices. 
In the majority of cases, the acoustic units 
themselves were manufactured for NOL by 
commercial companies such as the Brush De- 
velopment Company. These are listed in this 
volume under the manufacturer’s name. The 
NOL, in addition, developed a velocity hydro- 
phone standard, the SV type, a number of 
which were calibrated by USRL. This hydro- 
phone is described in Section 5.1.3. 

The David Taylor Model Basin submitted a 
number of tourmaline gauges to the USRL for 
calibration and these are discussed in Section 
6.7. A number of special test equipments de- 
veloped by the David Taylor Model Basin also 
were calibrated by USRL. These, however, in 
general employ acoustic devices of commercial 
manufacture and are listed herein in the manu- 
facturer’s name. 

The Signal Corps General Development Labo- 
ratory at Fort Monmouth, New Jersey, has 
designed two GR type offshore harbor defense 
systems. The GR-5 unit employs twenty-four 
T22 hydrophones. A smaller offshore unit, the 
GR-7, contains eight T37-T1 hydrophones. 
These hydrophones, as well as the systems, were 
developed by the Signal Corps and were tested 
by the USRL. These units are described in Sec- 
tion 5.1.4. 


[confidential 


194 



196 


NAVAL LABORATORIES’ DESIGNS 


K-Type Hydrophone 

Type: Tourmaline Crystal. 

Designer: Naval Research Laboratory. 

Reference: USRL calibration letter of July 7, 1944, to U. S. Naval Mine 
Warfare Test Station. 

Use: For underwater sound measurements in the frequency range from 
10 c to 15 kc. 

Description: The transducer element is a stack of four tourmaline disks, 
each % in. thick and 2% in. in diameter, connected electrically in parallel. 
The crystal stack is cemented to a brass backing plate 1% in. in thick- 
ness, which in turn is backed by a cork disk Vs in. in thickness. This 
assembly is contained in an oil-filled steel cartridge which has a sound- 
transparent window of po, rubber. The cartridge and preamplifier are 
mounted in an 11-in. cylindrical steel housing. 

The preamplifier is two-stage with inverse feedback. The plate supply 
is 135 V, and the filament supply 6 v. 


SUMMARY 


197 



Figure 1. Receiving response and preamplifier 
gain, K-4 hydrophone. 



Figure 2. Measured threshold, K-4 hydrophone. 




Figure 4. K-4 hydrophone. 




198 


NAVAL LABORATORIES’ DESIGNS 


^ Small Object Locator 

Designer: Naval Research Laboratory. 

Reference: NDRC Report No. 6.1-srll30-1979, December 19, 1944.^^® 

Use: For locating small objects in the water. 

Description: The small object locator is similar to the British Asdic 135 
in principle. It comprises three main parts: (1) a signal pulse generator, 
(2) a transducer, and (3) a tuned receiving amplifier and recorder. The 
unit supplied for test by USRL was equipped with a QBG projector (for 
characteristics see Chapter 2). 

A chemical recorder similar to the British unit is provided which, for 
better visibility, uses a pinkish paper rather than the tan paper used in 
the British unit. In addition, arrangement is made for arc recording, 
which gives a more permanent record than the chemical recorder. The 
recorder has four styli instead of one in order to present more detail. 

Provision is made in the small object locator for automatic volume 
control [A VC] and variable contrast by means of a subtraction circuit, 
which is similar to that in the British device. 




200 


NAVAL LABORATORIES’ DESIGNS 


SV Velocity Type Hydrophone 

Type: Permanent Magnet Pressure Gradient. 

Designer: Naval Ordnance Laboratory. 

Reference: NDRC Report No. C4-sr20-291, October 27, 1942.^^^ 

Use: Low-frequency hydrophone standard. 

Description: Two Duralumin hemispheres which are screwed together 
contain a heavy permanent magnet which is mounted flexibly on soft 
rubber. A coil is rigidly mounted on this sphere. The sphere and the coil 
partake of the velocity of the sound at low frequencies. Thus a relative 
motion is obtained between the coil and the magnet, generating alternat- 
ing voltages in the coil. In order that the sphere move with the sound, the 
wavelength of the sound must be considerably longer than the diameter 
of the sphere, which is 2% in. This limits the response of the instrument 
to frequencies below 10 kc. 


OPEN CIRCUIT VOLTS IN OB VS 1 VOLT 


SUMMARY 


201 


90 





Figure 6. Receiving response, SV hydrophone. 


Figure 8. SV hydrophone. 


(confidentiaiT^ 


202 


NAVAL LABORATORIES’ DESIGNS 


T22 and T37-T1 Hydrophones 

Type: Moving Coil Permanent Magnet. 

Designer: Signal Corps General Development Laboratory, Fort Mon- 
mouth, New Jersey. 

Reference: NDRC Report No. C4-sr20-294, November 13, 1942.^^^ 

Use: In GR-5 and GR-7 offshore harbor defense units. 

Description: The two types of hydrophone are identical in principle but 
differ in size, the T37-T1 being one-half the size of the T22. The outer wall 
of the cylinder, which is of Alnico steel, constitutes the permanent magnet 
of the hydrophone. A tube through the center of the cylinder connects the 
two diaphragms in an assembly somewhat like a “dumbbell.” A coil, 
located in the air gap of the magnetic circuit, is fastened to one of the 
diaphragms. 

The GR-5 system employs twenty-four T22 hydrophones. The GR-7 off- 
shore unit, which is a small edition of the GR-5, contains a row of eight 
T37-T1 hydrophones. Four of these are spaced at 1-ft intervals in each 
half of the beam. The beam is capable of being rotated through 180° in 
the horizontal plane. The systems are designed for binaural listening at 
audio frequencies, the hydrophones in the left half of the beam being 
connected through suitable amplifiers and receivers to the left ear, and 
those in the right half to the right ear of the observer. 



SUMMARY 


203 



180 


Figure 9. Directivity patterns, T22 hydrophone. 



Figure 11. Calculated threshold, T22 hydro- 
phone. 



MAGNETIZING COIL 



MOVING 
COIL 


DIAPHRAGM 



DIAPHRAGM 


RUBBER 

COVERING 


PERMANENT MAGNET 


Figure 13. T37-T1 hydrophone. 



REACTANCE- OHMS 


Chapter 6 

NDRC DIVISION 6.1 DESIGNS 


INTRODUCTION 

T his chapter covers the underwater acous- 
tic instruments designed and, in most cases, 
built by laboratories established by Division 6 
of the National Defense Research Committee 
[NDRC]. For the most part only devices 
calibrated by the USRL have been included, 
although some additional instruments are de- 
scribed. The designs of the following labora- 
tories are included: Columbia University Di- 
vision of War Research at the U. S. Navy 
Underwater Sound Laboratory, New London 
[CUDWR-NLL], Harvard Underwater Sound 
Laboratory [HUSL], Massachusetts Institute 
of Technology Underwater Sound Laboratory 
[MIT-USL], and University of California Di- 
vision of War Research at the U. S. Navy 
Radio and Sound Laboratory, San Diego 
[UCDWR]. In addition, two of the NDRC 
projects in which the USRL has been actively 
engaged over an extended period of time are 
described in individual sections so as to provide 
a unified picture of the work done in connec- 
tion with them. These projects are: (1) Tour- 
maline gauges, which include designs by the 
David Taylor Model Basin [DTMB] and the 
Stanolind Oil and Gas Company. (2) Scanning 
sonar systems. 


6 2 INSTRUMENTS DESIGNED AND CON- 
STRUCTED BY COLUMBIA UNIVERSITY 

This section describes the hydrophones that 
were calibrated by the USRL for Columbia 
University, Division of War Research, at the 
U. S. Navy Underwater Sound Laboratory, 
Fort Trumbull, New London, Connecticut. 

One of the main design efforts of the New 
London laboratory has been the development 
of magnetostriction listening units, although 
the attention of the laboratory, of course, has 
by no means been confined to these units. A 
variety of crystal hydrophones have been used 
for listening and other purposes, but usually 


these were adopted from designs by other 
agencies, especially the Brush Development 
Company of Cleveland, Ohio. 

The magnetostriction principle of design 
was advocated by the New London laboratory 
because it permitted the construction of in- 
herently simple and rugged units. The same 
considerations led the U. S. Navy to adopt, in 
pre-war days, magnetostriction echo-ranging 
projectors. The trend in echo ranging has been 
away from magnetostriction and toward crystal 
devices. The reasons, as outlined in Chapter 2, 
are (1) improvements in crystals (Y-cut 
Rochelle salt and especially ADP) and (2) the 
higher output and efficiency obtainable with 
crystals. For listening devices, the advantages, 
if any, of crystals are less pronounced. The 
difficulties of having crystals respond well at 
the lower audio frequencies are well known, 
and at these frequencies there is probably little 
choice between the two types of transducers 
from the efficiency standpoint. Furthermore, 
for listening, efficiency is less important since 
added gain in the receiving amplifier can com- 
pensate for it, provided the threshold of the 
hydrophone is sufficiently low. The latter, 
theoretically at least, can be reduced to any 
desired value by increasing the size of the unit. 
This can readily be done for the New London 
designs by extending their length. 

Below resonance the hydrophone response of 
magnetostriction underwater sound devices in- 
creases with frequency. It can be shown that 
this is an inherent characteristic of magneto- 
striction. The added flux caused by magneto- 
striction is proportional to the pressure : 

6 = Cp + do, 

where 6 is the total flux, p is the pressure, C is 
the proportionality constant, and Oo is the flux 
that would exist if the material were not mag- 
netostrictive. 

The induced voltage then is proportional to 
the rate of change of the flux, so that 

eg = jo^Cp = C'fp, 

where oj = 27rf and C' = proportionality con- 


rCONFIDEXTIA^ 


204 


CUDWR-NLL INSTRUMENTS 


205 


stant. On the basis of the ship’s sounds and the 
background noise decreasing with frequency, 
this increase in response has been considered 
advantageous by the New London labora- 
tory. ^22 

Magnetostriction designs generally are of 
low impedance. From the standpoint of the 
maximum permissible length of cable that can 
be attached to the hydrophone without exces- 
sive loss or noise pickup, the low impedance 
of the magnetostriction devices as compared to 
crystal units presents a real advantage. In 
many cases it obviates the need for an under- 
water preamplifier. 

The New London magnetostriction devices 
are invariably “line hydrophones.” A line has 
maximum response in all directions normal to 
the axis, but the piston’s response is unidirec- 
tional and sharp discrimination exists between 
the pickup of sound from the front and rear 
of the device. Offhand, this discrimination on 
the part of the piston would appear to be of 
considerable advantage in locating objects by 
listening. Since, however, this discrimination 
depends on the ratio of the wavelength and the 
diameter of the piston,^^*^ a very large piston is 
required to provide substantial discrimination 
at low frequencies. For instance, in order to 
have a discrimination of 10 db at 500 c, a 
piston must have a diameter of no less than 
4 ft. 

Several methods have been used by the New 
London laboratory to provide front and rear 
discrimination for the line hydrophones. These 
methods in general consist in using baffles^^^ 
to reduce response on one side of the hydro- 
phone, or in using two units^^^ connected in 
such a way to a phasing network that their 
output is combined when the sound comes from 
one direction and tends to cancel when the 
sound comes from the opposite direction (see 
Section 6.6.5). 

Figure 1 shows a directivity pattern for a 
continuous line, and Figure 2 for a theoretical 
piston. The one is expressed in terms of the 
length in wavelengths and the other in terms 
of the diameter in wavelengths. It will be noted 
that, for the same maximum dimensions, the 
line has a narrower beam width but the piston 
has lower side lobes. There has been much dis- 


cussion concerning any possible advantages for 
listening inherent in the narrow beam of the 
line hydrophone and any possible advantages 
due to the lower side lobes of the circular pis- 
ton. It is, of course, possible to change these 
factors by “tapering” or its inverse, so that 
actually these differences may not be so im- 
portant. Tapering has been used in a number 
of New London designs to reduce the magni- 
tude of the side lobes of their line hydro- 
phones.^^® 

The following are some of the principal ap- 
plications of magnetostriction hydrophones 
that have been made by the New London labo- 
ratory. 

1. Tubular magnetostriction hydrophones 
have been used for harbor defense.^^^ These 
hydrophones were designed for the audio fre- 
quency range and consisted of a nickel tube in 
which a longitudinal coil with laminated core 
was located. The tube is permanently magne- 
tized by means of the coil, the flux passing 
through the coil and returning through the 
two sides of the tube. (See Figure 3.) The 
usual length for these hydrophones was 4 ft 
and 6 ft.^^® These units were hung vertically in 
the water to detect any approaching surface 
vessel or submarine (see Section 6.6.6). 

2. In order to better define the direction of 
sound pickup, a toroidal magnetostriction 
hydrophone was developed by the New London 
laboratory. (See Figure 4.) Since a torus usu- 
ally is bidirectional, methods for discriminating 
against rear response were applied to this unit. 
These consisted of using a baffle or a system 
combining two identical units with a phasing 
network.127 Section 6.6.5.) 

3. In order to improve the efficiency of the 
design, a wood core was used, cylindrical in 
contour, and closely conforming to the internal 
diameter of the nickel tube. The hydrophone 
coil is wound over this wood cylinder, which 
also positions the iron core. This type of con- 
struction is used in the JP listening unit. (See 
Figure 5.) 

4. Further development of the magnetostric- 
tion hydrophone resulted in a toroidally wound 
cylindrical hydrophone (Figure 6). This type 
of design was finally adopted by the New Lon- 
don laboratory, and practically all later New 


206 


NDRC DIVISION 6.1 DESIGNS 



Figure 1. Directivity pattern for a continuous line. 



DB BELOW NORMAL INCIDENCE 


CUDWR-NLL INSTRUMENTS 


207 



DIAMETER OF PLATE IN WAVE LENGTHS 


Figure 2. 


Directivity pattern for a circular plate. 


lONFIDENfffi; 


208 


NDRC DIVISION 6.1 DESIGNS 


London designs were of that construction. The 
D-16 Mark IV hydrophones are examples of 
this design (see Section 6.6.1). Two section 
units about 2 ft in length, equipped with a 
baffle to provide rear discrimination, are used 
in the Directional Radio Sono Buoy developed 
by the New London laboratory. 

5. A 37-in. magnetostriction line hydrophone 
has been adopted for the U. S. Navy JP listen- 



Figure 3. Straight hydrophone, laminated core. 

ing equipment for listening from submarines, 
COG 51053.^^2 A further improvement in this 
equipment resulted in the design of the model 
JT sonar equipment by the New London labo- 
ratory. This uses the NL-124 magnetostriction 
unit, which consists of ten sections of per- 
manent magnet units toroidally wound. The 
design is tapered for side lobe reduction and 
includes a baffle for rear response reduction.^^® 
(See Section 6.6.3.) 



Figure 4. Toroidal hydrophone. 

^ 3 INSTRUMENTS DESIGNED AND CON- 
STRUCTED BY HARVARD UNIVERSITY 

The instruments designed and built by the 
Harvard Underwater Sound Laboratory which 
have been calibrated by the USRL are: B19-B, 
B19-H, HP-4, Sword Arm, CR Sonar, and ER 
Sonar. The B19-B and B19-H are used as USRL 
standard hydrophones and are covered in Sec- 


tions 1.4.14 and 1.4.15. The Sword Arm and 
HP-4 are experimental models designed for 
Navy use and are discussed in Sections 2.7.46 
and 2.7.47. The scanning sonars are discussed 
in Section 6.8. 


^ 4 INSTRUMENTS DESIGNED AND CON- 
STRUCTED BY THE MASSACHUSETTS 
INSTITUTE OF TECHNOLOGY 

Instruments designed and built by the Under- 
water Sound Laboratory at the Massachusetts 



Figure 5. Straight hydrophone, laminated core 
with additional wood core. 


Institute of Technology and calibrated by the 
USRL are discussed herein. The tourmaline 
gauges are included in Section 6.7.3 and the 
CMF, HK types, and XMX hydrophones which 
were used as USRL standards are to be found 
in Sections 1.4.18, 1.4.19, and 1.4.21, respec- 
tively. In addition, the XPA, HU, and HP (used 
with the PAR sound level indicator) are con- 
tained in Sections 6.6.9, 6.6.8, and 6.6.7 respec- 
tively. 



phone. 

Various types of electroacoustic coupling 
were employed in the MIT designs to obtain 
devices for special uses, in particular for meas- 
urement of noise sources, noisemakers, and ex- 


UCDWR INSTRUMENTS 


209 


plosive sounds. These applications required 
low-sensitivity devices with a low-frequency 
response and mechanical strength to withstand 
high pressure. The tourmaline gauges satisfied 
these requirements. The HU is also a low- 
sensitivity device with mechanical strength. 
The CMF which has a good low-frequency re- 
sponse can also be used to obtain absolute 
calibrations. The HP hydrophone and PAR 
sound level indicator were used for calibration 
as well as measurements. 


INSTRUMENTS DESIGNED AND CON- 
STRUCTED BY THE UNIVERSITY OF 
CALIFORNIA 

The instruments described in this chapter 
were selected by the University of California, 
Division of War Research as representative of 
the transducers designed by that division. In- 
cluded in this selection are some instruments 
which were not calibrated by the USRL. In 
this case, UCDWR calibrations are used. Other 
instruments representing older types were 
omitted from the selection even though they 
had been calibrated by the USRL. The origin of 
the data used herein, of course, is clearly shown 


by the references given in each case. The fol- 
lowing are types which were calibrated by the 
USRL but are not included in the selection pre- 
sented herein: 

BDl: NDRC Report No. 6.1-sr20-614, March 
30, 1943.133 

GDI: NDRC Report No. 6.1-sr20-614, March 
30, 1943.133 

CY4 : NDRC Report No. 6.1-srll30-1637, July 
17, 1944.113 (CY4 Sample 3A is described in 
Section 6.6.11.) 

The FM Scanning Sonar, which is also a 
UCDWR development, is described in Section 

6.8.3. 

The UCDWR had one group at San Diego 
which was engaged in the design of instru- 
ments mostly of the piezoelectric type. All the 
instruments covered herein use either ADP or 
Rochelle salt crystals for the active elements. 
Special designs were obtained by varying the 
size and number of crystals, and by '‘shading” 
to improve directivity. 

The UCDWR also operated an underwater 
sound calibration station at Sweetwater about 
5 miles from San Diego. The calibrations of 
their devices given herein, other than the USRL 
calibrations, were obtained by the UCDWR at 
Sweetwater. 


I^ ^OXFIDEXTIAL 


210 


NDRC DIVISION 6.1 DESIGNS 


^ ^ NDRC DIVISION 6.1 INSTRUMENTS 

D-16 Mark IV-D Hydrophone 

Type: Magnetostriction. 

Operating range: 200 c to 60 kc. 

References: NDRC Report No. 6.1-sr20-885, July 7, 1948.^^^ 

NDRC Report No. 6.1-sr20-871, May 14, 1943.^®^ 

NDRC Report No. 6.1-srll30-1193, December 17, 1943.1^1 

Use: Sound element in expendable nondirectional radio sono buoy. 

Description: Upon a cylindrical tube of unannealed nickel, a coil is 
closely wound in such a manner that half of each turn is adjacent to the 
inner wall and the other half adjacent to the outer wall. The so-called 
“tomato can” (see Figure 11) has a diameter of approximately 3 in. and 
a length of 5 in. The type of insulation used between the turns and the 
tube depends on the wire. In one example, the space between the winding 
and the tube was filled with rubber, in another case, with Lucite. Precau- 
tions are taken in the manufacture to avoid air bubbles between the tube 
and winding. 

Experimental models, the so-called “A” type hydrophones, were con- 
structed to study the effect on directivity of air cell rubber inside the 
winding. 



NDRC DIVISION 6.1 INSTRUMENTS 


2II 



Figure 7. Directivity pattern, D-16 Mark IV-D 
hydrophone at 9.6 kc. 



0.1 


1.0 10.0 
frequency in kc 


100.0 


Figure 8. Receiving response, D-16 Mark IV-D 
hydrophone. 



Figure 9. Calculated threshold, D-16 Mark IV-D 
hydrophone. 



1200 


1000 


800 


600 


400 


200 


Figure 10. Impedance, D-16 Mark IV-D hydro- 
phone. 




212 


NDRC DIVISION 6.1 DESIGNS 


JP Hydrophone (COG 51053) 

Type: Magnetostriction. 

Operating range: Audio frequencies. 

Manufacturer: Astatic Corporation, Youngstown, Ohio. 

References: NDRC Report No. 6.1-srll30-1163, February 2, 1944.^^2 
NDRC Report No. 6.1-sr20-942, July 22, 1943.^" 

UCDWR Report No. C17, November 8, 1943.i3« 

Use: In JP-1 listening system. 

Description: The JP hydrophone is of the straight wood core mag- 
netostriction type. The unit consists of a nickel cylinder about 40 in. in 
length and 2 in. in diameter, in which a cylindrical wood core extends 
most of the length. The coil is wound on this core with the turns running 
parallel to the axis of the tube. Across the diameter of the tube, cutting 
the wood core in half and extending the length of the tube, is a laminated 
core. A streamlined rubber-covered baffle provides directivity. 


jEoNFIDEXTIAL/ 


NDRC DIVISION 6.1 INSTRUMENTS 


213 



90 “ 


180 “ 

Figure 12. Directivity pattern, JP (COG 
51053) hydrophone at 10 kc. 



Figure 14. Calculated threshold, JP (COG 
51053) hydrophone. 



Figure 13. Receiving response, JP (COG 
51053) hydrophone. 



Figure 15. Impedance, JP (COG 51053) hydro- 
phone. 



Figure 16. JP hydrophone assembly (COG 
51053). 


Figure 17. Cross-sectional view of magneto- 
striction unit, JP (COG 51053) hydrophone. 


214 


NDRC DIVISION 6.1 DESIGNS 


NL.124 Hydrophone (CQA 51074) 

Type: Magnetostriction. 

Operating range: 100 c to 65 kc. 

References: NDRC Report No. 6.1-srll30-2135, February 12, 1945.^®' 
NDRC Report No. 6.1-srll28-2215, May 25, 1945.i"6 

Use: For JT sonar equipment. 

Description: The NL-124 hydrophone is a 5-ft permanent magnet mag- 
netostriction line, consisting of 10 sections which are tapered to reduce 
side lobes. The sections are toroidally wound. The hydrophone is plastic- 
filled and covered with neoprene rubber compound. A 4-wire cable permits 
the use of separate channels for the two halves. The hydrophone is 60 in. 
long, 2% in. in diameter, and weighs approximately 22 lb. A 129-A baffle 
is used with the hydrophone to provide front-to-back discrimination. 



Figure 18. Directivity pattern, NL-124 hydro- 
phone at 9.5 kc (series aiding). 



Figure 19. Directivity pattern, NL-124 hydro- 
phone at 9.5 kc (series opposing). 


^CONFIDENTIAL j] 


NDRC DIVISION 6.1 INSTRUMENTS 


215 



Figure 20. Receiving response, NL-124 hydro- 
phone. 



Figure 22. Impedance, NL-124 hydrophone. 



Figure 21. Calculated threshold, NL-124 hydro- 
phone with baffle. 


Figure 23. NL-124 hydrophone with NL-129-A 
baffle. 



216 


NDRC DIVISION 6.1 DESIGNS 


^ NL.130 Hydrophone 

Type: Magnetostriction. 

Operating range: 200 c to 60 kc. 

Manufacturer: Astatic Corporation, Youngstown, Ohio. 

Reference: NDRC Report No. 6.1-srll30-1838, October 19, 1944.^^® 

Use: In noise level monitoring installations and for the depth charge 
indicator. 

Description: The NL-130 hydrophone is a magnetostriction device in 
which the permanent magnet transducer element is contained in a IOYq in. 
by 21/^ in. rubber cover with sealed polystyrene end fittings. The device 
is vacuum-filled with a phenolic resin composition which is polymerized 
to form a hard elastic solid. The transducer element consists of a heat- 
treated nickel tube. An Alnico magnet is silver-soldered into a slot in this 
tube. A toroidal winding having 270 turns of No. 27 gauge wire is 
applied to the nickel tube. A wooden dowel inside the tube furnishes a 
pressure release. A special feature of this hydrophone is its mechanical 
ruggedness, which makes it suitable for use at great depth. 



Figure 24. Directivity patterns, NL-130 hydro- 
phone. 


/CONFIDP^yrlAir^ 


NDRC DIVISION 6.1 INSTRUMENTS 


217 



FREQUENCY IN KC 


Figure 25. Transmitting response, NL;130 
hydrophone. 



phone. 


I- 5 



Figure 26. Receiving response, NL-130 hydro- 
phone. 



Figure 28. Impedance, NL-130 hydrophone. 



Figure 29. NL-130 hydrophone. 



218 


NDRC DIVISION 6.1 DESIGNS 


^ Toroidal Magnetostriction Hydrophone 

Type: Magnetostriction. 

Operating range: Audio frequencies. 

References: BTL Technical Memorandum, April 29, 1942.^23 

NDRC Report No. C4-sr20-155, August 3, 1942.^27 
NDRC Report No. C4-sr20-214, July 1, 1942.^25 
NDRC Report No. C4-sr20-284, September 25, 1942.^29 

Use: For JP listening system. 

Description: This design is a modification of the tubular magnetostric- 
tion hydrophone. The nickel tube is formed into a torus and the coil is 
wound around the inner circumference, hence no core is needed. The 
tube is mounted by means of four U-bolts on an annular steel backing 
plate. A sound-absorbent pad made of Corprene (rubber and cork) is 
cemented to the back of the steel plate to reduce rear response. 

Another arrangement consists of two magnetostriction hydrophones 
suspended coaxially. Amplifiers are associated with each unit and an 
electric delay network is employed with one of them so that their outputs 
add if the sound is from one direction and cancel when the sound is from 
the opposite direction. As shown by the chart, this balance is effective 
only over a limited frequency range. 


0 ® 



Figure 30. Directivity pattern, toroidal mag- 
netostriction hydrophone at 5 kc. 


RELATIVE RESPONSE IN DB 


NDRC DIVISION 6.1 INSTRUMENTS 


219 




Figure 32. Receiving response, toroidal mag- 
Figure 31. Difference between front and rear netostriction hydrophone, 

response, toroidal magnetostriction hydrophone. 




Figure 33. Calculated threshold, toroidal mag- 
netostriction hydrophone. 


Figure 34. Impedance, toroidal magneto- 
striction hydrophone. 



FASTENING 




Figure 35. Toroidal magnetostriction hydro- 
phone. 




REACTANCE- OHMS 


220 


NDRC DIVISION 6.1 DESIGNS 


Tubular Magnetostriction Hydrophone 

Type: Magnetostriction. 

Operating range: Audio frequencies. 

References: BTL Technical Memorandum, April 29, 1942.^23 

NDRC Report No. C4-sr20-196, August 15, 1942.^^® 

NDRC Report No. C4-sr20-203, September 1, 1942.128 
NDRC Report No. C4-sr20-095, March 17, 1942.122 

Use: For harbor defense and overside listening from small surface 
patrol craft. 

Description: The hydrophone consists of a cylindrical nickel tube, di- 
vided internally across the diameter by a laminated strip of Permalloy 
extending its length. The nickel tube is permanently magnetized so that 
no external polarizing batteries are needed. The hydrophone coil is v^ound 
lengthAvise around the laminations. An impinging sound wave produces 
alternating stress in the nickel tube and a corresponding periodic variation 
in its permeability, thus modulating the flux and inducing an alternating 
voltage in the coil. Arrows indicate the direction of flux paths through 
the core and tube. 


VOLTAGE ACROSS 135 OHMS IN OB 

VS I VOLT FOR A SOUND FIELD OF I OYNE/SQ CM 


NDRC DIVISION 6.1 INSTRUMENTS 


221 


0 * 



Figure 36. Directivity pattern, tubular mag- 
netostriction hydrophone at 9.5 kc. 



Figure 37. Receiving response, tubular mag- 
netostriction hydrophone. 


w 2 - 


3° 




¥ 


0.1 


FREQUENCY IN KC 


100 


Figure 38. Calculated threshold, tubular mag- 
netostriction hydrophone. 



Figure 39. Impedance, tubular magnetostric- 
tion hydrophone. 



Figure 40. Tubular magnetostriction hydro- 
phone. 




I ) ^ /A f 






222 


NDRC DIVISION 6.1 DESIGNS 


HP Hydrophone 


Type: Magnetostriction. 

Designer: Underwater Sound Laboratory, Massachusetts Institute of 
Technology. 

Reference: NDRC Report No. C4-sr20-132, July 15, 1942.^26 

Use: Working standard. 

Description: The HP hydrophone differs in only two significant features 
from HK hydrophones. (1) In HP, the crystal pack is mounted directly in 
a square hole in the solid brass hydrophone head, with thin sheets of 
insulator where necessary. In HK, the crystals are first mounted in a 
bakelite holder which is then fitted into a circular hole in the hydrophone 
head. (2) The preamplifier of the HP hydrophone contains a calibrating 
resistance, which is not installed on the HK preamplifier. Otherwise, the 
characteristics of the HP are very similar to those of the HK hydrophones 
(see Section 1.4.19). 

The HP is used with the PAR sound level indicator which was also 
designed at MIT. This apparatus can measure sounds of frequency from 
0.2 to 10 kc within a few decibels and from 10 to 50 kc with greater error. 
Pressure levels can be measured in the range from 30 to 75 db above one 
dyne per sq cm and the equipment can work into any recorder with an 
input impedance greater than 10,000 ohms. 



OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF I DYNE /SO CM 


NDRC DIVISION 6.1 INSTRUMENTS 


223 


HU Hydrophone 


Type: Magnetostriction. 

Designer: Underwater Sound Laboratory, Massachusetts Institute of 
Technology. 

References: NDRC Report No. 6.1-sr20-619, May 6, 1943.^® 

NDRC Report No. 6.1-sr20-879, June 19, 1943.21 

Use: Measurements in high-intensity sound fields. 

Description: The HU is a low-sensitivity hydrophone for sound pressure 
measurements in high-intensity sound fields of frequencies from 20 to 
1,000 c. The magnetostrictive element is a nickel bar which is magnetized 
by momentary application of a 90-v polarizing potential. The housing 
above the bar contains an equalizer circuit designed to operate into a 
5,000-ohm load. 



Figure 41. Receiving response, HU hydro- 
phone. 



CONFID] 


224 


NDRC DIVISION 6.1 DESIGNS 


6 . 6.9 


XPA Projector 


Type: X-Cut Rochelle Salt Crystal. 

Operating range: 2 to 50 kc. 

Designer: Underwater Sound Laboratory, Massachusetts Institute of 
Technology. 

Reference: NDRC Report No. 6.1-srll30-1631, June 29, 1944.^^^ 

Description: The crystal block contains 144 X-cut Rochelle salt crystals 
connected in parallel. A Vs-m. rubber diaphragm is cemented directly to 
the crystal face. The crystal bank is mounted in a brass frame and the 
entire assembly has been dipped in latex rubber. The projector should be 
driven with a constant current input from a 250-ohm to a 500-ohm source, 
depending upon the frequency range. 

Overall dimensions: 131/^ by 3% by V 2 in. 

Impedance in ohms: 


Frequency 


(kc) 

0.5 

1.0 

2.0 

5.0 

10.0 

20.0 

50.0 

100.0 


Resistance 


122.8 

69.4 
29.9 
24.2 

44.4 

19.5 

93.6 

12.6 


Reactance 


— y2345 

— jll90 

— i613 

— j221 

— il24.7 

— i41.4 

— y6.36 

— y70.5 


Efficiency: — 12.5 db at 6 kc. 





NDRC DIVISION 6.1 INSTRUMENTS 


225 



Figure 43. Directivity patterns, XPA pro- 
jector in a plane perpendicular to axis at 6 kc 
and 10 kc. 

o 


0 



Figure 44. Directivity patterns, XPA pro- 
jector in a plane perpendicular to axis at 20 kc 
and 60 kc. 



Figure 45. Transmitting response, XPA pro- 
jector. 



Figure 46. XPA projector. 



BRASS CASE 
DIPPED IN 
LATEX 


RUBBER 

DIAPHRAGM 


Figure 47. Dimensional drawing, XPA pro- 
jector. 


CONFIDENTIAL 



226 


XDRC DIVISION 6.1 DESIGNS 


CJJ-78256 Serial 20 Sound Head 

Type: Z-Cut ADP Crystal. 

Designer: University of California, Division of War Research. 

Reference: Calibrated by UCDWR. Letter from C. J. Burbank to R. S. 
Shankland, August 27, 1945. 

Description: The CJJ sound head is a cylinder 28 in. long and 1414 in. 
in diameter. It contains a transmitting projector and a recei\ing hydro- 
phone, each acoustically and electrically isolated and enclosed in a steel 
shell ha\’ing a 2-in. thick pC rubber window as its face. The projector is 
nearer the mounting studs. The free space within the cylinder is filled with 
electrical grade castor oil. 

The projector element is composed of 12 bars, arranged into a 90° 
sector of a cylinder; each bar has 28 Z-cut ADP elements, arranged in 
groups of four and all connected in parallel. The indi\idual elements are 
0.80 in. long, 0.50 in. wide, and 0.25 in. thick. The bars, each 8^4 in. long, 
% in. wide, and % in. thick, have a layer of porcelain approximately 
0.05 in. thick bonded to the crystal-mounting surface, which serves to 
insulate the ciy’stals electrically from the metal. 

The receiver element is lobe-suppressed, with an inner section 5 in. in 
diameter and an outer under-driven section 9.5 in. in diameter. The 
408 ADP crystals, the same size as those in the projector, are arranged 
in the section in groups of three, all connected in parallel, while, in the 
outer section, the individual crystals in each group of three are connected 
in series and the groups in parallel. The individual crystals in the two 
sections are therefore connected to give a voltage ratio of three to one. 
The layer of porcelain between the crj’stals and the ?i-in. thick backing 
plate is approximately 0.04 in. thick. 

Each of the units has balanced series tuning coils chosen to operate 
with it. Foam rubber is used in the following places: (1) the back of the 
receiver backing plate, (2) the edges of the transmitter crystals, except 
the radiating edge, (3) between the groups of crystals in the receiver 
array, (4) on the opposite faces of the partition between the transmitter 
cavity and the receiver cavity, (5) behind the bars of the transmitter, and 
(6) on an interior baffle behind the transmitter unit. 



Figure 48. Transmitting response, CJJ-78256 
serial 20 sound head. 



FREQUENCY Iff KC 


Figure 49. Receiving response, CJJ-78256 Serial 
20 sound head. 


|C(»>'FIDEyTi^ 


OHMS 


NDRC DIVISION 6.1 INSTRUMENTS 


227 



Figure 50. Directivity pattern, CJJ-78256 serial 
20 sound head at 42 kc. 




Figure 52. Impedance, transmitter section of 
CJJ-78256 serial 20 sound head. 



Figure 51. Impedance, hydrophone section of Figure 53. Exploded view, CJJ-78256 serial 20 

CJJ-78256 serial 20 sound head. sound head. 




228 


NDRC DIVISION 6.1 DESIGNS 


CY4 Sample 3A Transducer 

Type: Y-Cut Rochelle Salt Crystal. 

Designer: University of California, Division of War Research. 

Reference: Calibrated by UCDWR. Letter from C. J. Burbank to R. S. 
Shankland, August 27, 1945. 

Description: The CY4 Sample 3 A is a cylindrical device consisting of a 
crystal unit housed in a standard 1-pt olive can. The crystal assembly is 
composed of 20 Y-cut Rochelle salt crystals, each in., in a 

straight stack, all connected in parallel. Undesired radiation from the 
sides of the stack is suppressed by strips of Corprene; and disks of 
neoprene, separated from the ends of the crystal assembly by Lucite 
spacers, serve to center the unit in the can. The space within the can not 
otherwise occupied is filled with electrical grade castor oil. 


'ONFIDEK 


PRESSURE AT I METER IN OB VS I DYNE/SO CM 
PER WATT AVAILABLE POWER FROM 26200 OHMS 


NDRC DIVISION 6.1 INSTRUMENTS 


229 



90 * 


180 * 


Figure 54. Directivity pattern, CY4 sample 3 A 
transducer at 25 kc. 



transducer. 




Figure 55. Transmitting response, CY4 sample 
3A transducer. 


Figure 57. Impedance, CY4 sample 3A trans- 
ducer. 


CO 


REACTANCE IN OHMS 




230 


NDRC DIVISION 6.1 DESIGNS 


^ ® EP2Z Transducer 

Type: Z-Cut ADP Crystal. 

Designer: University of California, Division of War Research. 

Reference: Calibrated by UCDWR. Letter from C. J. Burbank to R. S. 
Shankland, August 27, 1945. 

Description: This is a “flashlight” type unit, housed in a cylindrical 
aluminum case in. in diameter. The transducer element is a 2V2-in. 

diameter circular array of 98 Z-cut ADP crystals, each 0.470x0.088x0.50 
in., all connected in parallel, Cycle-Welded to a 40-shore neoprene dia- 
phragm Vs in. thick which acts as a sound window. The unit is air-filled. 


0 * 



Figure 58. Directivity pattern, EP2Z-6 trans- 
ducer at 110 kc. 


NDRC DIVISION 6.1 INSTRUMENTS 


231 


O o 

el 90 

52^ 


80 


Ul UJ 

u)® 70 
2< 


® ^ 
® (T 
C UJ 

a. a. 










































* 

^ 



— 




















10 


1000 


Figure 59. 
transducer. 


FREOyENCY IN KC 

Transmitting response, EP2Z-6 



FREQUENCY IN KC 

Figure 60. Receiving response, EP2Z-6 trans- 
ducer. 



00““ 90 ioo no 120“^ 130 140 

FREQUENCY IN KC 


Figure 61. Impedance, EP2Z-6 transducer. 



Figure 62. Crystal assembly, EP2Z-6 trans- 
ducer. 



Figure 63. Housing of EP2Z-6 transducer. 


\confidentiaB 



232 


NDRC DIVISION 6.1 DESIGNS 


^ ^ FE2Z Transducer 

Type: Z-Cut ADP Crystal. 

Designer: University of California, Division of War Research. 

Reference: Calibrated by UCDWR. Letter from C. J. Burbank to R. S. 
Shankland, August 27, 1945. 

Description: This unit consists of a roughly diamond-shaped array 
of 98 Z-cut ADP crystals, each 0.574x0.50x0.25 in., all connected in parallel. 
Cycle- Welded to the %-in. neoprene window of a cast Meehanite case about 
12 in. long, 5 in. wide, and 6 in. deep, in whose top compartment the 
crystal unit is backed by foam rubber. (Figure 68 shows a shallower 
aluminum case.) The unit is gas-filled. 



NDRC DIVISION 6.1 INSTRUMENTS 


233 



Figure 64. Directivity pattern, FE2Z-1 trans- 
ducer at 90 kc. 



Figure 66. Receiving response, FE2Z-1 trans- 
ducer. 








































t/) 

5i 



















to o 
^ o 

UJ ^ 











































































^ L- 

1^90 
— o 









1 

















/ 











q: q. 

UJ 







y 












80 

5 < 







/ 

















































to > 



















trS 10 

Q. 0. 

100 

1C 


FREQUENCY IN KC 


Figure 65. Transmitting response, FE2Z-1 
transducer. 



Figure 67. Impedance, FE2Z-1 transducer. 



Figu^ 68. FE2Z-1 transducer. 


Nqonfidential^ 


REACTANCE IN OHMS 



234 


NDRC DIVISION 6.1 DESIGNS 


^ ^ GA2 Transducer 

Type: 45° X-Cut Rochelle Salt Crystal. 

Designer: University of California, Division of War Research. 
Reference: NDRC Report No. 6.1-sr20-873, May 18, 1943.^^^ 

Also calibrated by UCDWR. Letter from C. J. Burbank to 
R. S. Shankland, August 27, 1945. 

Description: The active face of the transducer is approximately 8 in. 
square. It consists of 8 rows of 26 crystals each, covered with a rubber 
diaphragm. The space between the crystals and diaphragm is oil-tilled. 
The case is cast iron, with dimensions as shown in Figure 74. 




OXFIDEXTIAL I 


XDRC DIVISIO?^ 6.1 INSTRUMENTS 


235 


0 * 



Figure 69. Directivity pattern, GA2 transducer 
at 50 kc. 



Figure 70. Transmitting response, GA2 trans- 
ducer. 



Figure 72. Impedance, GA2 transducer. 



Figure 73. Crystal assembly, GA2 transducer. 



Figure 71. Receiving response, GA2 transducer. 



Figure 74. Dimensional drawing, GA2 trans- 
ducer. 


IDEXTIAL 


REACTANCE IN 



236 


NDRC DIVISION 6.1 DESIGNS 


^ ^ GD16-17 Transducer 

Type: 45° Y-Cut Rochelle Salt Crystal. 

Designer: University of California, Division of War Research. 

Reference: Calibrated by UCDWR. Letter from C. J. Burbank to R. S. 
Shankland, August 27, 1945. 

Description: The GD16-17 No. 1868 consists of 168 45° Y-cut Rochelle 
salt crystals, each %xlx% in., connected in parallel, cemented in close 
array to the porcelain-enameled surface of a V 2 -in. steel backing plate, 
forming an active face approximately 4 x 41/2 in. A strip of l^-in. thick 
canvas bakelite is cemented to the backing plate on either side of the 
crystal assembly. The transducer element is nested in Corprene in a cast 
Meehanite case approximately 6 in. square and 3 in. deep, with a neoprene 
sound window bonded into the Meehanite. All the space within the case 
not otherwise occupied is filled with electrical grade castor oil. 


, C OyFIDEXTIAL f 


NDRC DIVISION 6.1 INSTRUMENTS 


237 



o 


Figure 75. Directivity pattern, GD16-17 trans- 
ducer at 80 kc. 


O 2 

SS 

\o 
z Si; 

ei 

(o £ 

CD u 

z o 

— Q. 

70 


to 5 

UJ QZ 


60 

































































































































FREQUENCY IN KC 

Figure 76. Transmitting response, GD16-17 
transducer. 



10 100 


FREQUENCY IN KC 

Figure 77. Receiving response, GD16-17 trans- 
ducer. 



Figure 78. Impedance, GD16-17 transducer. 



Figure 79. GD16-17 transducer. 



reactance in 





238 


NDRC DIVISION 6.1 DESIGNS 


^ ^ GD34Z-1 Transducer 

Type: Z-Cut ADP Crystal. 

Designer: University of California, Division of War Research. 

Reference: Calibrated by UCDWR. Letter from C. J. Burbank to R. S. 
Shankland, August 27, 1945. 

Description: This transducer, air-filled, consists of a transducer element 
of 72 Z-cut ADP crystals, each in., all connected in parallel, 

cemented together in pairs, six pairs per row, and Cycle- Welded to a pC 
rubber sound window 1% in. thick. Imbedded in the pC window between 
rows of crystals are five steel alloy bars 1 in. high and Vs in. wide, with 
% in. space center-to-center of the bars. The total array is approximately 
4V4 x 4% in., and is fitted into a square cast Meehanite case about 3 in. deep. 


^NFIDENTIAL ^ 


NDRC DIVISION 6.1 INSTRUMENTS 


239 



Figure 80. Directivity pattern, GD34Z-1 trans- 
ducer at 49 kc. 




10 100 
FREQUENCY IN KC 


Figure 81. Transmitting response, GD34Z-1 
transducer. 




Figure 82. 
ducer. 


Receiving response, GD34Z-1 trans- 


Figure 84. Rear view, GD34Z-1 transducer 
crystal assembly. 


CONFIDENTIAJ 





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TOURMALINE GAUGES 


241 


6 7 TOURMALINE GAUGES 

Tourmaline gauges have been used in oil 
exploration work to measure the strength and 
time of arrival of explosion waves and their 
reflections in the ground. 

These designs have been adapted to the 
measurement of underwater explosive sounds. 
The USRL has calibrated such devices for the 
David Taylor Model Basin, the Woods Hole 
Oceanographic Institution [WHOI], and the 
MIT Underwater Sound Laboratory. Most of 
the instruments submitted were manufactured 
by the Stanolind Oil and Gas Company of Tulsa, 
Oklahoma. 

The measurement of explosive sounds im- 
poses a number of special requirements on a 
hydrophone.i^^ Some of these requirements may 
be summarized as follows. 

1. The mechanical strength of the device 
must be sufficient to withstand the shock. 

2. The device must be capable of carrying 
the highest peak sound pressure without over- 
loading.^ 

3. The response must be uniform over a wide 
frequency range.^^^ 

For satisfactory measurements of explosive 
sounds, uniform response is required from fre- 
quencies below 100 c to the megacycle region. 
In the present state of instrument design this 
can only be approximated. The usual design 
uses a very small crystal having a natural 
frequency at, or possibly above, the maximum 
frequency of interest. Tourmaline generally is 
preferred because it possesses a volume piezo- 
electric effect which the other generally avail- 
able crystals do not have. As a consequence, 
diffraction affects the response to a lesser de- 

^ See discussion in STR Division 6, Volume 10, 
Chapter 5. 


gree because flexure set up by the diffracted 
wave and the pressure at the edges do not affect 
tourmaline .^^2 addition, the face of the hydro- 
phone is made small to minimize diffraction 
effects, and its thickness is made small to 
obtain high-frequency resonance. When this is 
done, the pressure of the shock wave does not 
change appreciably in the time required to 
traverse the crystal. This design has the fur- 
ther advantage that below the natural fre- 
quency phase shift is linear with frequency, 
which is necessary if oscillograms of the sound 
waves are to be taken.^^^ 

It will be realized that such a hydrophone is 
very inefficient and has a very high impedance. 
There are two methods for taking care of this 
situation. One consists in associating a pre- 
amplifier with the crystal as closely as possible, 
keeping the length of leads between the two a 
minimum. The preamplifier then is located 
underwater at the point where the wave is 
measured ; hence, it must be designed to with- 
stand the full power of the explosion. In the 
other method, which has been used by WHOI, 
instead of the open-circuit voltage, the electric 
charge on the crystal is measured. This meas- 
urement is independent of the length of cable 
intervening between the crystal and the pre- 
amplifier. Thus it is possible to move the latter 
to a safe distance, out of the water entirely. 

To measure small explosion charges of the 
order of magnitude of a No. 6 blasting cap, the 
USRL has used the XMX hydrophone described 
in Section 1.4.21. Heavy explosions undoubtedly 
would shatter the Rochelle salt crystal used for 
the active element in this instrument. The only 
available piezoelectric materials that can with- 
stand such extreme pressures are quartz and 
tourmaline. 

b See STR Division 6, Volume 10, Chapter 4. 


^xEinioSiL^-^ 


242 


NDRC DIVISION 6.1 DESIGNS 


TMB Tourmaline Gauge 

Type: X-Cut Tourmaline Crystal. 

Designer: David Taylor Model Basin. 

Reference: USRL calibration letter to Rear Admiral H. S. Howard 
dated October 19, 1944. 

Use: For measuring high-pressure underwater sound. 

Description: This unit uses a small tourmaline crystal, or crystals, en- 
closed in a soft rubber cover with a 2-in. long neck. One or more insulated 
leads are carried inside a Vs-in. copper tube which is grounded through 
the water, thus forming a shield. The design is similar to that of the 
Stanolind Oil and Gas Company tourmaline gauges. The useful frequency 
range extends to about 1 me. 




TOURMALINE GAUGES 


243 



Figure 85. Receiving response, TMB tourmaline 
gauge. 



Figure 87. Impedance, TMB tourmaline gauge. 


( 



Figure 86. Calculated threshold, TMB tourma- 
line gauge. 




Figure 88. TMB tourmaline gauge. 


I 


pONFIDENTE i: 


REACTANCE IN OHMS 


244 


NDRC DIVISION 6.1 DESIGNS 


^ TMB-Tl Hydrophone 

Type: X-Cut Tourmaline Crystal. 

Designer: David Taylor Model Basin. 

Reference: USRL calibration letter to Rear Admiral H. S. Howard 
dated October 19, 1944. 

Use: To measure high-pressure underwater sounds. 

Description: The TMB-Tl hydrophone uses a small tourmaline disk with 
a molded rubber cover. A %G-in. diameter cylindrical brass tube of about 
2 -in. length couples the unit to a single-stage preamplifier. The latter is 
contained in a cylindrical housing 2 in. in diameter by 8 V 2 in. long. The 
useful range of this instrument extends to about 50 kc. 


C ONFIDENTIAL '7 


OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF I DYNE /SO CM 


TOURMALINE GAUGES 


245 



Figure 89. Receiving response, TMB-Tl hydro- 
phone. 


FREQUENCY IN KC 

Figure 90. Measured threshold, TMB-Tl hydro- 
phone. 



ENTTAL 


246 


NDRC DIVISION 6.1 DESIGNS 


^ ^ ^ Stanolind Oil and Gas Company Tourmaline Gauges 

Type: X-Cut Tourmaline Crystal. 

Designer: Stanolind Oil and Gas Company, Tulsa, Oklahoma. 

References: NDRC Report No. 6.1-srll30-1828, September 8, 1944.^^^ 
NDRC Report No. 6.1-srll30-1971, October 31, 1944.^^^ 

Use: To measure high-pressure underwater sound. 

Description: Designs of the Stanolind Oil and Gas Company have been 
calibrated by the USRL for the Underwater Explosion Research Labora- 
tory at the Woods Hole Oceanographic Institution and for the MIT Under- 
water Sound Laboratory. These instruments have generally been used by 
the Navy for underwater explosion measurements. 

Either two or four tourmaline disks are employed in each instrument. 
The diameter of these disks varies between in. and 1% in. The disks 
are either in. or % in. thick. The smaller dimensions apply to the 
instrument with the highest frequency range. The disks are silver and 
copper plated and welded together. The outside faces are covered with 
metal foil or gauze for shielding, and are connected to a copper tube which 
is grounded by the water. If four crystals are used, the midpoint of the 
pile-up is also strapped to this tube. The other faces are connected in 
parallel to an insulated conductor inside the tube which forms the high 
side of the circuit. The crystals are covered with a molded rubber jacket 
or with DR tape to keep water away from them. A cement, “Bostik,"’ is 
applied under the cover to exclude air and provide high insulation resist- 
ance. In order to minimize electric pickup, it would be preferable if both 
sides of the crystal were kept off ground and two insulated leads were 
brought out. 

The useful frequency range, depending on the size and construction of 
the crystal, extends from 50 kc to 1 me. 


OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF I DYNE /SO CM 


TOURMALINE GAUGES 


247 



Figure 92. Directivity pattern, Stanolind Oil 
and Gas Company tourmaline crystal hydro- 
phone No. 529. 



Figure 94. Receiving response, Stanolind Oil 
and Gas Company tourmaline gauge (4 disks). 



Figure 93. Receiving response, Stanolind Oil 
and Gas Company tourmaline gauge (2 disks). 



Figure 95. Receiving response, Stanolind Oil 
and Gas Company tourmaline crystal hydro- 
phone No. 529. 




^ ofvS°^?YNE/lQ CM THRESHOLD PRESSURE IN OB VS I DYNE /CM 


248 


NDRC DIVISION 6.1 DESIGNS 



Figure 96. Calculated threshold, Stanolind Oil 
and Gas Company tourmaline gauge (2 disks). 



Figure 98. Impedance, Stanolind Oil and Gas 
Company tourmaline crystal hydrophone No. 
529. 



Figure 97. Calculated threshold, Stanolind Oil 
and Gas Company tourmaline crystal hydro- 
phone No. 529. 



COPPER WIRE 


-^COPPER 

TUBING 



BOUND WITH 
THREAD 8. 
RUBBER COATED 



Figure 99. Stanolind Oil and Gas Company 
tourmaline gauge. 



f 


REACTANCE- OHMS 


SCANNING SONAR 


249 


6 8 SCANNING SONAR 

Introduction 

Present types of sonar gear used in echo 
ranging (see Chapter 2) operate on the “beam’' 
or “searchlight” principle: the emission by a 
projector at a given bearing of directed super- 
sonic pulses and the reception by the same pro- 
jector of audibly heterodyned echoes. By re- 
peating this procedure at 5° changes in the 
projector bearing, the complete (180°) forward 
sector is covered. When a target is discovered 
by its echo, its bearing is found by “cut-ons” 
or the use of Range information is sup- 

plied by the chemical recorder.^82 

Such a procedure requires approximately 2.5 
min for the complete coverage of the 180° sec- 
tor by successive pings of the searchlight beam. 
Disadvantages result from the difficulty en- 
countered by the beam in keeping on a target 
(in part eliminated by BDI), from the possi- 
bility that a target may be much closer than 
the maximum attainable range before detection 
due to the time required to cover the sector by 
pinging, and finally, from the comparatively 
low search efficiency^^^ for a given maximum 
range due to the small number of pings emitted 
in any given direction. 

As a result, scanning sonar systems have 
been developed by HUSL and by UCDWR to 
maintain sensitivity in all directions simultane- 
ously through a rapid continuous scanning of 
wide azimuth sectors of 180° or more. Theoreti- 
cally, this should permit detection of all targets 
within the maximum available range. 

In addition, the scanning sonar systems are 
designed to present a plan position indication 
[PPI] of all targets within range on the screen 
of a cathode-ray oscilloscope. This will provide 
bearing and range information to supplement 
that supplied by the chemical recorder. The 
use of visual plan position indicating is in- 
tended to permit the maintenance of continu- 
ous contact with the target. 

Disadvantages incurred by scanning sonar 
with respect to the conventional searchlight 
gear are largely due to the relatively high 
visual recognition differential, and to the high 
noise level within the rather broad filters of the 


gear; the smaller acoustic pressure in a given 
direction, due to the horizontal breadth of the 
emitted beam, can be overcome by a higher 
acoustic power output. 

This chapter includes a compilation and dis- 
cussion of the physical characteristics of scan- 
ning sonar systems as obtained in USRL tests, 
and a general analysis of the expected opera- 
tional effectiveness of scanning sonar in echo 
ranging versus submarines as determined by 
these characteristics, particularly the corre- 
sponding effectiveness of conventional search- 
light gear. 


Harvard University Systems 
General Description 

Two systems of scanning sonar, capacity 
rotation [CR] and electronic rotation [ER], 
have been developed by the Harvard Under- 
water Sound Laboratory. They operate on the 
principle of “flooding” the area of interest with 
sound by periodically pulsing supersonic waves 
from a projector in all directions in the hori- 
zontal plane. A multielement transducer is 
used, as shown in Figure 100, and during pro- 
jection all elements are connected in parallel. 
In reception, the same transducer is made di- 
rectional and its directivity pattern is rotated 
at high speed in the horizontal plane. This is 
accomplished by connecting each element of 
the transducer to a corresponding element of a 
scanning switch. The switch couples into a 
single network the output of a relatively small 
number of adjacent transducer elements, in- 
troducing suitable phase displacement for mak- 
ing these elements into a directional hydro- 
phone. The output of the switch is amplified 
and applied to the brightness control of a 
cathode-ray tube so that a spot identifies an 
echo. Ranges are measured by applying po- 
tentials which initiate a diverging spiral sweep 
in the cathode-ray tube indicator at the instant 
that the pulse is emitted so that the distance 
of the spot representing the echo from the 
center of the screen is approximately propor- 
tional to the range of the target producing this 
echo. By synchronizing the rotation of the 
spiral sweep with the rotation of the scanning 




250 


NDRC DIVISION 6.1 DESIGNS 


switch, the spot bearings are made to corre- 
spond with target bearings. 

The distinction between CR and ER sonar 
is in the method employed for producing the 
scanning switch action. In CR sonar this is 
accomplished by rotation (at 30 rps) of one 
of a pair of condenser plates relative to the 
other, the outputs of the transducer elements 
being connected to the stator plate. 

In ER sonar the scanning switch action is 
purely electronic and makes use of a system of 
triodes, one for each element of the transducer. 


acterized by the fact that the receiving beam, 
in effect, is rotated electrically by a commuta- 
tor arrangement, the transducer being station- 
ary. 

The transducer of the XQHA system (see 
Figures 101, 102) consists of 48 stacks of 
laminations, each of which may be referred to 
as an element. (The elements are numbered 
consecutively from 1 to 48 and are read clock- 
wise when the transducer is suspended in the 
water from a ship. The 0° axis is taken to be 
midway between elements No. 48 and No. 1.) 


MULTI - ELEMENT 

transducer 


X-AXIS 



r-Axis 


-CATHODE -RAY TUBE 

Figure 100. Schematic diagram, Harvard scanning sonar showing multielement transducer. 


These triodes are connected to the transducer 
elements into a directional hydrophone. The 
directivity pattern is rotated at the frequency 
of a low-frequency alternating current (200 to 
500 c). 

Because of the difference in the methods of 
producing scanning switch action, it has been 
found that ER sonar is suited for the use of 
very short pulses (^ 2 msec), while CR sonar 
is readily adapted for pulses sufficiently long 
for auditory monitoring at a given bearing 
(^30 msec). 

XQHA Capacity Rotation Scanning Sonar 

The XQHA CR scanning sonar system pro- 
vides a means of obtaining a plan position indi- 
cation of acoustically reflecting objects within 
the range of its transducer. The system is char- 


When transmitting, each of the elements is 
connected in series with a tuning condenser 
(0.012 /xf), the 48 units then connected in 
parallel and finally shunted by a tuning coil. 
In this arrangement the transducer is connected 
across the output of the power amplifier. The 
system on transmitting is hence nondirectional 
in the horizontal plane. To provide sufficient 
power to produce pressures in any direction 
which are equivalent to those provided by con- 
ventional directional echo-ranging equipment, 
an impulse-type driver (see Figure 103) is 
used which employs large storage condensers 
for the plate supply of the output power tubes. 
An exponentially decaying pulse of 35-msec 
duration with about 3-db attenuation in this 
time is thus obtained, which has, on the lowest 
keying rate, a power of about 8 kw, resulting in 


( ^)NFIDENTIAL gj 






SCANNING SONAR 


25] 


an acoustic power output of about 3 kw. The 
average power input to the transmitter is about 
550 w. 

On receiving an entirely different arrange- 
ment is used. Each 0.012 ^f condenser is 
shunted across the corresponding transducer 



Figure 101. Transducer, XQHA system. 


element and the outputs of the elements are 
then individually connected, each to the input 
of a small impedance transformer. The 48 
transformers are mounted in a circle on a 
glass disk which forms the stator of a rotating 
capacity commutator (see Figure 104). The 
outputs of the transformer are connected to 
metallized segments (see Figure 105) similarly 
arranged about the other surface of the glass 
disk and each forms one plate of a condenser. 
The rotor consists of a second glass disk similar 
to the first and mounted on the same axis as the 
stator with an air gap of 0.0035 in. between 
them. On the rotor are also mounted 48 metal- 
lized segments which form the second plate 
of the condenser. In scanning operation, the 

f 


rotation of the rotor successively brings each 
segment on the rotor opposite each segment of 
the stator. When a sound wave is incident on 
the transducer, each element generates a volt- 
age whose magnitude and phase depend upon 
the orientation of that element with respect to 
the direction of incidence of the- sound wave. 
To provide directional reception, it is therefore 
necessary to combine the voltages of a number 
of elements with proper attenuation and phase 
shift so that the resultant voltage will be large 
only when the sound wave approaches from a 
given direction. This is accomplished by a lag 
line mounted on the rotor. Sixteen of the 
metallized segments on the rotor are connected 
to proper positions along the lag line. By the 
attenuation and phasing thus produced, the 



Figure 102. Transducer, XQHA system with 
rubber cover removed. 


output voltage from the lag line will be large 
only when sound is arriving from a direction 
within a small angle about the radial line which 
bisects the 16 elements of the transducer, whose 
corresponding stator plates are “meshed” with 



252 


NDRC DIVISION 6.1 DESIGNS 


the sixteen active condenser plates on the rotor. 
Hence, as far as the output of the lag line is 
concerned, the receiving system is directional, 
and the directional pattern on receiving can 
be rotated, without rotation of the transducer 
itself, simply by a rotation of the rotor. In 
scanning operation, the rotor has an angular 



Figure 103. Driver, XQHA system. 


velocity of 30 rps, so that the beam on receiv- 
ing is rotated with a corresponding velocity. 
The output of the lag line is brought out from 
the commutator by slip rings and is then ap- 
plied to a preamplifier. Actually two capacity 
commutators are employed, operating in par- 
allel from the transducer. The first, described 
previously, is known as the scanning commuta- 
tor; the second is identical in construction, ex- 
cept that instead of being rotated at 30 rps by 
a motor, the position of the rotor is set by a 
separate servo system to any desired orienta- 
tion, which may be changed at will by a control 



Figure 104. Receiver unit, XQHA system show- 
ing rotating capacity commutator. 



Figure 105. Rotor and stator, XQHA system 
showing rotating capacity commutator. 


on the control panel. This commutator is used 
for listening steadily in a fixed direction and 
is hence known as the listening commutator. 




SCANNING SONAR 


253 



Its output is brought out in the same way and 
goes to another preamplifier. 

The output of the scanning commutator, after 
amplification and rectification, is applied to the 
brightening grid of a cathode-ray tube (see 
Figures 106, 107) which provides the plan 


Figure 106. Exposed view, cathode-ray tube and 
indicator-control unit of XQHA. 

position indication. An expanding spiral sweep 
is provided to this tube, so that between the 
transmission of one pulse and the succeeding 
one, the spot on the screen scans out the area 
of the screen in a spiral from center to edge. 
The sweep is synchronized with the rotation of 
the scanning rotor so that the spot makes one 


rotation on the screen for one rotation of the 
scanning rotor. 

The operation of the scanning system is then 
as follows : A pulse of 35-msec duration is sent 
out in all directions from the transducer on 
transmission. The switch to reception is then 


Figure 107. Cathode-ray tube and indicator- 
control unit of XQHA. 

made. If a target is present at some orienta- 
tion, an echo will reach the transducer from 
this direction at some later time. The rotating 
receiving beam will pick up the echo on one of 
its rotations at this time and this signal will 
then be transmitted to the brightening grid 
of the screen. In the meantime, the spot (that 




254 


NDRC DIVISION 6.1 DESIGNS 


is the potential position of the spot) will have 
traveled out in a spiral from the center of the 
screen to a radius proportional to the time 
since the pulse was transmitted into the water. 
When the echo is received, the brightening grid 
is activated, and hence a bright spot (actually 
a small arc) appears on the screen at a distance 
from the center proportional to the range of 
the target and at some characteristic orienta- 
tion which gives the bearing of the target. If 
a number of targets are present, each will ap- 
pear on the screen in its proper position with 
respect to range and bearing. Hence a map 
of all acoustically reflecting objects lying within 
acoustic range of the transducer will be pre- 
sented on the screen almost continuously (one 
remapping for each transmitted pulse). Vari- 
ous refinements are present in the system, but 
they will not be discussed here. 

The listening channel is employed differently. 
The output of the listening commutator after 


amplification goes to a loudspeaker, thus pre- 
senting audio reception of the echoes from the 
direction to which the listening commutator is 
oriented. Means are also provided to indicate 
by an electronic cursor on the cathode-ray 
screen the direction to which the listening 
rotor is sensitive. Thus, when an echo appears 
on the screen, the listening rotor can be aligned 
in the direction in which the echo was received 
as shown on the screen, and hence, both visual 
and aural reception for the same target can be 
achieved. 

Results of USRL Calibration Tests on 
XQHA Capacity Rotation Scanning Sonar^^i 

The USRL has carried out extensive cali- 
bration tests on the transmitting and receiving 
responses, the directivity, the impedance, and 
the efficiency of the XQHA system. These tests 
are summarized as follows. 


Table 1 * 


Directivity index on transmission 
Directivity index on reception (effective) 

Projector efficiency of transducer — untuned (at low electric power input) 

Projector efficiency of transducer — tuned (at low electric power input) 

Projector efficiency of single transducer element (No. 16) — untuned (at low electric 
power input) 

Projector efficiency (at full electric power input of 1 1 kw) 

Output pressure at 1 meter in db vs 1 dyne per sq cm (at full electric power input 
of 11 kw) 


-11.5 db 
-28.0 db 

- 7.0 db (20%) 

- 4.2 db (38%) 

- 2.4 db (65%) 

- 7.4 db (18.2%) (acoustic power 

output = 2 kw) 

-115.3 db 


* All values refer to resonant frequency —25.5 kc. 



SCANNING SONAR 


255 


Transmitting Tests on Transducer Alone — 
All Transducer Elements Connected in Parallel 



Figure 108. Directivity pattern, XQHA trans- 
ducer with all elements in parallel in horizontal 
plane at 25.5 kc. 



Figure 109. Directivity pattern, XQHA trans- 
ducer with all elements in parallel in vertical 
plane at 25.5 kc. 



FREQUENCY IN KC 

Figure 110. Transmitting response, XQHA 
transducer with all elements in parallel. 


Transmitting Tests on Transducer with Asso- 
ciated Tuning Circuits 


O” 



Figure 111. Directivity pattern, XQHA trans- 
ducer with associated tuning circuits in hori- 
zontal plane at 26 kc. 


jTONFIdEXTIAL ^ 


256 


NDRC DIVISION 6.1 DESIGNS 



Figure 112. Transmitting response, XQHA 
transducer with associated tuning circuits. 


Receiving Tests on the Transducer Aloiie 



Figure 114. Directivity pattern, single element 
of XQHA transducer in horizontal plane at 26 
kc. The 0° axis of the transducer is indicated 
by To. 



Figure 113. Impedance, XQHA transducer with 
associated tuning circuits. 


-7C 


: o 

'3 -9C 


i S -IOC 

18 

: 

’< HIO 

I (£ 

o 



FREQUENCY IN KC 

Figure 115. Receiving response, single element 
of XQHA transducer. 







SCANNING SONAR 


257 


Receiving Tests on Transducer ivith Shunt 
Condensers, Commutator, and Lag Line ® 



Figure 116. Directivity pattern, XQHA trans- 
ducer in horizontal plane at 26 kc. Transducer 
rotated with rotor fixed at 0°. 



Figure 118. BDI directivity pattern, XQHA 
transducer in horizontal plane at 25.5 kc. Voltage 
taken at output lag line. Rotor setting at 0°. 
Left half only. 



Figure 117. Directivity scanning pattern, 
XQHA transducer in horizontal plane at 25 kc. 
Source on 0° axis of transducer, listening rotor 
rotated through 360°. 



® Measurements made at output of lag line give 
essentially open circuit voltages applied to input of 
XQHA preamplifier. 


Figure 119. BDI directivity pattern, XQHA 
transducer in horizontal plane at 25.5 kc. Voltage 
taken at output lag line. Rotor setting at 0°. 
Right half only. 




258 


NDRC DIVISION 6.1 DESIGNS 



Figure 120. BDI directivity pattern, XQHA 
transducer in horizontal plane at 25.5 kc. Voltage 
taken at output lag line. Rotor setting at 0°. 
Parallel aiding. 


0 » 



Figure 121. BDI directivity pattern, XQHA 
transducer in horizontal plane at 25.5 kc. Voltage 
taken at output lag line. Rotor setting at 0°. 
Parallel opposing. 



Figure 122. Receiving response, XQHA trans- 
ducer with rotor set at 0° and sound incident 
along the 0° axis of the transducer. (0° position 
of rotor is taken to be that for which the 16 
active condenser plates of the rotor are in 
register with elements 41 to 48 and 1 to 8 in- 
clusive, so that the beam pattern theoretically 
has its maximum along the acoustic 0° axis of 
the transducer.) 

Pbj^IDEimAL jfj 


# 


SCANNING SONAR 


259 


Tests on Transducer Driven by XQHA Oscil- 
lator (Full Electric Poiver Input) 



Figure 123. Wave form of the (30 msec) pulse. (A) Voltage applied to transducer. (B) Current into 
transducer. (C) Acoustic pulse in water as measured by a hydrophone. 



Figure 124. Directivity pattern, XQHA trans- 
ducer in horizontal plane at 25.5 kc. 


' /confidential £) 






260 


NDRC DIVISION 6.1 DESIGNS 


Test on Scanning Channel Circuits 



Figure 125. Gain in scanning channel from a-c 
voltage input to scanning preamplifier to d-c 
voltage on brightening grid of cathode-ray 
oscilloscope, as a function of (1) frequency (gain 
control setting at 26.5 kc) and (2) gain con- 
trol setting (frequency at 25 kc). 



Figure 126. Relation between a-c voltage ap- 
plied to preamplifier and d-c voltage of brighten- 
ing grid of cathode-ray oscilloscope at 25.5 kc. 



Figure 127. Noise developed by system and ap- 
pearing on brightening grid of cathode-ray 
oscilloscope (gain control 90 kc; frequency 26.5 
kc: (1) entire system in operation with scanning 
motor running, (2) entire system in operation 
with scanning motor shut off. 


SCANNING SONAR 


261 


Dynamic Scanning Directivity Pattern. The 
dynamic scanning directivity pattern is the 
variation of voltage on the brightening grid as 
a function of time when correlated with the 
angle between the orientation of the source and 
the instantaneous direction of maximum sensi- 
tivity of the beam. The dynamic scanning di- 
rectivity pattern is not identical with the scan- 
ning directivity pattern giving the a-c voltage 
at the output of the lag line (see Figure 128)*^ 



Figure 128. Wave forms as rotating beam 
traverses the sound source: (A) a-c signal at 
output of lag line, (B) d-c signal applied to 
brightening grid of cathode-ray oscilloscope. 

because of the nonlinear action of the rectifier. 
This nonlinear action serves to suppress side 
lobes. 

Bearing Accuracy Tests. The USRL has also 
made tests on the bearing accuracy of XQHA 
scanning sonar for visual observation on the 
oscilloscope screen and with use of the associ- 

‘^A l-kc tuning signal is superimposed on the photo- 
graphs. 


ated BDI circuit. Both methods gave target 
bearings (the target was an independent sound 
source) with errors of the order of 1 degree. 
At least part of the bearing error seemed to 
arise from improper positioning of the listening 
rotor by the synchro systems. 

Electronic Rotation Scanning Sonar 

In addition to the CR scanning sonar dis- 
cussed above, Harvard University has also de- 
veloped an electronic rotation scanning sonar. 
As has already been mentioned, in this device 
the receiving beam is rotated electronically 
rather than mechanically. As a result of the 
rapid rate of rotation which is necessary be- 
cause of the electronic rotation, a very wide 
pass band in the scanning channel (^ 8 kc) is 
required for ER scanning sonar; as a result, 
a noise level inherently higher than in CR scan- 
ning sonar is always present.® 

The USRL has calibrated an early model 
of ER scanning sonar obtaining response and 
directivity patterns. However the equipment 
has never worked very well and, it is under- 
stood, has been superseded by more satisfactory 
types. 


University of California System 
Frequency Modulated Sonar 

Frequency Modulated [FM] sonar is a de- 
vice for presenting a plan position indication of 
underwater objects within sonic range of the 
equipment. It is designed for installation on 
both submarines and surface vessels, e.g., A/S 
craft. 

Other vessels and their wakes, mines, tor- 
pedoes, sand banks, antisubmarine nets, in fact, 
any partially or completely submerged objects 
which are good supersonic reflectors, are repre- 
sented both audibly, by a constant pitch tone, 
and visually, by illuminated spots on a PPI 
oscilloscope screen in their proper position rela- 
tive to the operating ship. 

The operation of FM sonar equipment is as 
follows: An acoustic signal with a sawtooth 

® The width of the pass band of the scanning channel 
of CR sonar (reckoned to the 10-db points) is about 2 
kc. See Figure 124. 





262 


>DRC DIVISION 6.1 DESIGNS 


frequency modulation is injected into the water. 
The difference in frequency between an echo 
received from an object in the water and the 
signal being emitted at any instant is then 
a measure of the range of the object. The 
equipment can be broken down into the follow- 
ing components, each of which will be discussed 
separately (see Figure 129) : 

1. Oscillator (and associated power ampli- 
fier). 

2. Sound head. 


push-pull amplifier is so arranged as to blank 
the output signal during the time in which the 
“flyback” on the sawtooth takes place. The 
rate of repetition of the sawtooth is governed 
by a resistor which may be varied in three 
steps by the operator so as to give sawtooth 
periods of 4.5, 9, and 18 sec, respectively. This 
provides an adjustment for the range of the 
target. Thus the oscillator as a unit produces 
a linear sawtooth frequency-modulated signal 
with frequency variation from about 35 to 48 


filter and 

SWITCH POINTS 



3. Receiving circuit (modulator and ampli- 
fier). 

4. Analyzer. 

5. Indicator. 

Oscillator. The oscillator circuit consists of 
a regulated 370-v power supply, a linear saw- 
tooth oscillator, a positive-bias multivibrator, a 
low-pass filter, and a push-pull amplifier which 
is used to blank the signal during the recycling 
or “flyback” in the sawi;ooth. The frequency of 
the output signal from the multivibrator is 
governed by the voltage applied to its grid 
return. Since this voltage is a linear sawtooth 
voltage from the linear sawtooth oscillator, the 
output will be a sawtooth frequency-modulated 
signal. The harmonics of the multivibrator out- 
put are eliminated by the low-pass filter. The 


kc, and with a savd;ooth period which may be 
adjusted to the three values of 4.5, 9, or 18 sec. 
Part of the output of the oscillator is applied 
to the power amplifier and part is used as the 
injection voltage in the modulator. 

Power Amplifier. The power amplifier is a 
push-pull design with a rated power output of 
250 w. A potentiometer output control is in- 
cluded but the amplifier is normally operated at , 
maximum gain. 

Sound Head. The sound head is a cylinder 31 1 

in. long, covered by a rubber sleeve, which 
contains both the transmitter and receiving 
hydrophone (see Figure 130). The units are 
mounted on a flange on a standard QC column. 
The transmitter consists of an array of ADP 
crystals w^hose active surfaces form part of a 


*(5^^FIDENTIAL 


SCANNING SONAR 


263 



Figure 130. Sound head (FM sonar). 

cylindrical surface so as to give a beam width 
in the horizontal plane of about 80°. The beam 
width in the vertical plane is about 12°. The 
hydrophone consists also vof an array of crys- 


tals, but in this case the active surface is a 
circle 9 in. in diameter. Its beam is sharply 
directional with a beam width of about 12°. 
Both transducers are rigidly mounted to the 
shaft with their axes parallel, and they may 
be rotated together through a full 360°. 

The sound head is trained by a motor which, 
under ordinary operation, rotates it through 
540° (IV 2 revolutions), whereupon a revers- 
ing switch causes it to be rotated back through 
540°; reversal again takes place and the cycle 
is repeated regularly. The rate of rotation may 
be adjusted to between 2 and 4 rpm. The op- 
erator may also arrange to scan only a limited 
sector, or reverse the rotation direction at any 
instant. 

The transmitter is driven by the power 
amplifier, while the hydrophone signal is ap- 
plied to the receiving circuit. 

The operation of the units in practice is the 
following. When the sawtooth frequency-modu- 
lated signal is applied to the transmitter, sound 
is emitted into the water with a sawtooth 
frequency modulation over a sector 80° wide. 
If there is a target present, the reflected signal 



Figure 131. Frequencies of emitted and re- 
ceived signals as functions of time. 


from the target at the time it reaches the hydro- 
phone will differ in frequency from that being 
emitted at that instant from the projector be- 
cause of the frequency sweep, 'the equipment 
is so arranged that for any sawtooth period 
setting, the received signal from maximum 
range will arrive in a time equal to 1/6 of the 
sawtooth period. These relationships are shown 
in Figure 131, where the emitted frequency 
and the received frequencies from targets at 
maximum range and one-half maximum range 
are shown as functions of time. 



264 


NDRC DIVISION 6.1 DESIGNS 


Receiving Circuit. The receiving circuit con- 
sists of two components, a varistor detector and 
an amplifier. The signal received from the 
hydrophone is first passed through a 36 to 48 
kc band-pass filter and then goes to the varistor 
detector. The detector also receives an injection 
signal from the oscillator, the frequency of 
which is the instantaneous frequency of the 
sound being emitted by the transmitter. The 
circuit is designed to balance both the signal 
voltage and injection heterodyne voltage, leav- 
ing only the desired difference frequency. This 
output is filtered to eliminate any other fre- 
quency components which may be present. The 
difference frequency as a function of time is 
shown in Figure 131. The filter only admits 
the lower frequency so that the output of the 
filter is an almost continuous signal of the de- 
sired difference frequency. The amplifier to 
which this signal is applied is designed so that 
in the important difference frequency range 
(500 to 2,000 c), it has a rising characteristic 
of 12 db per octave and falls off rapidly outside 
these limits. This equalizes the detector output 
for various ranges, since the hydrophone signal 
varies approximately inversely as the fourth 
power of the range. Part of the output from 
the amplifier is used to operate a loudspeaker 
and part goes to the analyzer. The loudspeaker 
is used for aural monitoring by the operator. 

Analyzer. The analyzer consists of 20 band- 
pass filter networks, associated detectors, and 
an electronic switch. The signal received from 
the receiving circuit is applied across 20 band- 
pass filters with series-tuned inputs arranged 
in parallel. Each filter is a double-tuned, ca- 
pacity-coupled, band-pass network with a band 
width of about 75 c. The 20 filters cover the 
range from 500 to 2,000 c. Thus, the difference 
frequency from any target will pass through 
one (or possibly two) of the filters, the par- 
ticular filters through which it passes depend- 
ing on the difference frequency which in turn 
is a function of the range. 

The output of each filter is connected through 


a potentiometer to a corresponding detector, 
the potentiometers allowing equalization of the 
various filter outputs. The detectors are so 
arranged that they are relatively insensitive to 
signals of longer or shorter duration than an 
echo from a target as the transmitter is trained 
past it. This results in better discrimination 
against noises of short duration and reverbera- 
tion. The output from the detectors is used to 
control the acceleration potential in the cathode- 
ray tube of the indicator, and thus it controls 
the brightness of the spot. However, the out- 
puts are not fed directly to the indicator but 
are applied in sequence by an electronic switch. 
The output of each filter is allowed to activate 
the indicator only for a short time in each 1/60 
of a second. The sequence is that of increasing 
target range. The electronic switch is synchro- 
nized with the radial sweep on the oscilloscope 
so that the range is a linear function of dis- 
tance of spot from the center of the screen. 

Indicator. The indicator consists of a cathode- 
ray tube, a radial sweep circuit, and an ampli- 
fier. The amplifier is used to amplify the output 
from the analyzer detectors for application to 
the beam intensity control grid of the cathode- 
ray tube. The radial sweep of the spot on the 
oscilloscope, as stated, is synchronized with 
the electronic switch of the analyzer. A sine 
potentiometer mounted on the shaft of the 
sound head diverts the radial sweep in a direc- 
tion determined by the orientation of the sound 
head at the time. The net result on the screen 
is an almost continuous plan view of the sur- 
rounding area with bright spots representing 
the presence of acoustically reflecting objects. 

Results of USRL Calibration Tests on 
Frequency Modulated Scanning Sonar^^^ 

The USRL has carried out detailed calibra- 
tion tests on the transmitting and receiving 
responses, the directivity, and the impedance 
of the FM scanning sonar. These tests are sum- 
marized as follows. 




SCANNING SONAR 


265 


Calibration of Transmitter. 



180 


Figure 132. Directivity pattern, FM sonar 
transmitter in horizontal plane at 34 kc. 



90* 


Figure 134. Directivity pattern, FM sonar 
transmitter in horizontal plane at 50 kc. 


90 « 



90 - 


Figure 133. Directivity pattern, FM sonar 
transmitter in horizontal plane at 42 kc. 


0 - 



Figure 135. Directivity pattern, FM sonar 
transmitter in vertical plane through acoustic 
axis at 34 kc. 




.-qONKpENTIAL 


266 


NDRC DIVISION 6.1 DESIGNS 


0 * 



Figure 136. Directivity pattern, FM sonar 
transmitter in vertical plane through acoustic 
axis at 42 kc. 



90 


o 


Figure 138. Directivity pattern, FM sonar 
transmitter in vertical plane making a +30° 
angle with acoustic axis at 34 kc. 



o 


Figure 137. Directivity pattern, FM sonar 
transmitter in vertical plane through acoustic 
axis at 50 kc. 


0 » 



Figure 139. Directivity pattern, FM sonar 
transmitter in vertical plane making a +30° 
angle with acoustic axis at 42 kc. 



SCANNING SONAR 


267 


o» 



Figure 140. Directivity pattern, FM sonar 
transmitter in vertical plane making a +30° 
angle with acoustic axis at 50 kc. 


0 * 



180 * 


Figure 141. Directivity pattern, FM sonar 
transmitter in vertical plane making a — 30° 
angle with acoustic axis at 34 kc. 



ISO* 


Figure 142. Directivity pattern, FM sonar 
transmitter in vertical plane making a — 30° 
angle with acoustic axis at 42 kc. 



Figure 143. Directivity pattern, FM sonar 
transmitter in vertical plane making a — 30° 
angle with acoustic axis at 50 kc. 




268 


NDRC DIVISION 6.1 DESIGNS 



10 100 


FREQUENCY IN KC 

Figure 144. Transmitting response, transmitter 
unit of FM sonar. 



Figure 145. Receiving response, transmitter 
unit of FM sonar. 



Figure 146. Impedance, FM sonar transmitting 
unit (without cable). 


Calibration of Receiver 



180 


Figure 147. Directivity pattern, FM sonar re- 
ceiver in horizontal plane at 34 kc. 


0 * 



Figure 148. Directivity pattern, FM sonar re- 
ceiver in horizontal plane at 42 kc. 


TIAL 


JONFl 




SCANNING SONAR 


269 



Figure 149. Directivity pattern, FM sonar re- 
ceiver in horizontal plane at 50 kc. 


Figure 151. Directivity pattern, FM sonar re- 
ceiver in vertical plane at 42 kc. 




Figure 150. Directivity pattern, FM sonar re- Figure 152. Directivity pattern, FM sonar re- 
ceiver in vertical plane at 34 kc. ceiver in vertical plane at 50 kc. 


CKJNFIDENTIA 



270 


XDRC DIVISION 6.1 DESIGNS 



Figure 153. Transmitting response, FM sonar 
receiver. 



Figure 154. Receiving response, FM sonar re- 
ceiver. 



Figure 155. Impedance, FM sonar receiving 
unit (without cable). 


Relation of Operational Effective- 
ness of Scanning Sonar in A/S 
Operations to Its Physical 
Characteristics^ 

The general principles relating the opera- 
tional effectiveness of underwater sound de- 
vices to their physical design parameters, e.g., 
directivity and acoustic power output, have 
been discussed in detail. From these discus- 
sions it follows that for ease of analysis the 
A/S operation is first divided into three parts 
(treated in inverse chronological order) : at- 
tack, chase, detection. 

In the attack the criteria of operational effec- 
tiveness are the values of the blind time and 
of the depth error, in the chase the value of the 
bearing accuracy and the ability to maintain 
contact, and in detection (in “searching” or 
“shielding”) the values of the coverage rate 
and of the maximum range® at which contact 
can first be made.^^^ 

In the attack, both for scanning sonar as 
well as for searchlight gear, auxiliary close 
contact maintenance and depth determining 
equipment are necessary. Such auxiliary gear 
must satisfy the conflicting requirements of a 
short blind time and of an ability to measure 
depth with small errors, with reasonably long 
range. Assuming for the moment that scanning 
in the vertical plane is used, short blind times 
and small depth errors imply requirements on 
the vertical beam width and on the accuracy 
of bearing measurements on the PPI screen 
representing the vertical plane. 

In the chase, maintenance of contact depends 
on the vertical beam width. Regarding bearing 
accuracy during the chase, tests performed by 

f This is with particular reference to the XQHA 
CR system in comparison with present searchlight gear 
and with searchlight gear incorporating certain im- 
provements. 

s The maximum range is defined as that range at 
which the probability of detecting an echo from a sub- 
marine against the background is just 50 per cent; the 
coverage rate is defined as the equivalent area swept by 
the A/S ship per unit time in which there is certainty 
of detecting the submarine. The search efficiency e^, 
commonly adduced along with the maximum range 
r as a criterion of operational effectiveness in 

max 

“shielding,” can be expressed in terms of the coverage 
rate C and the maximum range by the equation = 
C/2r V (v is the relative ship-sub speed). 

max ' 


SCANNING SONAR 


271 


the USRL^^i indicate that visual observation on 
the PPI oscilloscope screen of the scanning 
sonar leads to bearing accuracies ^ 1 degree, 
i.e., bearing accuracies of the same order as are 
obtained with BDI attachment to the scanning 
sonar. This bearing accuracy is obtained on the 
PPI screen giving horizontal bearings, but pre- 
sumably comparable accuracy may be obtained 
on the PPI screen giving vertical bearings. 
Contact maintenance for a given vertical beam 
width is, of course, better with scanning sonar 
than with searchlight gear because of the 360° 
horizontal beam and the greater psychological 
certainty of visual presentation on the PPI 
screen; further, if the vertical beam is chosen 
as a reasonable compromise between the con- 
flicting demands of contact maintenance dur- 
ing chase and attack and those of small depth 
error, or if an auxiliary broad vertical beam^ 
and an auxiliary narrow beam “sword'^ pro- 
jector is used, both depth errors and blind times 
may be made sufficiently small. Thus it is seen 
that, regarding blind time, depth error, and 
bearing accuracy, scanning sonar with neces- 
sary auxiliary equipment is at least equal in 
performance to searchlight gear, while with 
respect to contact maintenance, scanning sonar, 
because of the PPI visual presentation feature, 
is greatly to be preferred to the searchlight 
type of equipment. 

Regarding detection, it is convenient first to 
estimate maximum ranges which may be ob- 
tained under comparable oceanographic condi- 
tions with scanning sonar and with searchlight 
gear. The pressure output at 1 m of XQHA 
scanning sonar is approximately 115 db vs 1 
dyne per sq cm,!®^ some 4 db higher than that 
of present searchlight gear (QBF, QCU, etc.). 
See Chapter 2. The background in the scanning 
sonar, as far as noise (largely self-noise) is 
concerned, is equivalent to the level in a band 
of approximately 2 kc (see Figure 125). Also 
for visual recognition on the PPI screen, the 
signal level must exceed that of the noise by 
some 5 db for 50 per cent recognition; this 
value for the 50 per cent visual recognition 
differential on the PPI screen was found in de- 

broad beam in the vertical plane required for 
close contact maintenance — short blind time may be 
obtained by using the output of a portion of the length 
of the cylindrical transducer. 


tailed visual recognition tests conducted by the 
USRL.i®3 Qn the other hand, the 100-msec 
ping signal, commonly used in searchlight sys- 
tems with aural recognition,^ can be recognized 
at a level some 10 db below a 2-kc noise back- 
ground (50 per cent aural recognition differ- 
ential of — 7 db with respect to noise in a 1-kc 
band) 

Further, the receiving beam has a directivity 
index ^ — 28 db for scanning sonar^®^ and 
^ — 23 db for searchlight gear (see Chapter 2) ; 
thus the effective noise background is ^ [5 — 
( — 10)] — 5 = 10 db higher for scanning sonar 
than for present searchlight gear. Again the 
reverberation level will tend to be higher in 
scanning sonar than in present searchlight gear, 
because of the higher signal output (4 db), 
^nd it will tend to be lower because of the 
shorter ping used, 30 rather than 100 msec 
(5 db), and the narrower receiving beam (5 
db). Moreover the 50 per cent PPI visual 
recognition differential versus reverberation is 
probably greater than that against noise (be- 
cause of the greater “peakiness'' of reverbera- 
tion) — it may be taken as ^ 7 db; on the other 
hand, the 50 per cent aural recognition dif- 
ferential versus reverberation is ^ 3 db.^^^ 
Thus the effective reverberation background is 
2 db lower in scanning sonar than in current 
searchlight gear. It is thus seen that under 
given oceanographic conditions and, of course, 
with the same frequency, i.e., the same trans- 
mission loss, the signal level is 4 db higher in 
scanning sonar than in present searchlight gear, 
the effective noise level is 10 db higher, and 
the effective reverberation level 2 db lower. 
As a result, noise limited ranges will be some- 
what shorter (about 10 per cent) with scanning 
sonar than with present searchlight gear and 
reverberation limited ranges somewhat longer 
(about 15 per cent). Of course, with scanning 
sonar, ranges will remain noise limited up to 


i The values of both the visual and the aural recogni- 
tion differentials used are obtained from tests wherein 
undistorted signals are injected into a thermal noise 
background. Actual signal distortion and a “peakiness” 
greater than that found in thermal noise will adversely 
affect both visual and aural recognition. The quantita- 
tive measure of this adverse effect must await studies 
on recognition differential as a function of signal dis- 
tortion and of noise “peakiness.” 


lOXFIDEXTIAL 


J 


272 


NDRC DIVISION 6.1 DESIGNS 


somewhat shorter distances from the echo- 
ranging vessel. 

This analysis leads to the conclusion that 
comparable maximum detection ranges may be 
expected from scanning sonar and from present 
searchlight gear under all oceanographic con- 
ditions. This expectation is borne out by actual 
sea tests. It should be recalled, however, that 



Figure 156. Detection probability as a func- 
tion of range. 


improvements have been suggested in search- 
light gear, namely, the use of a lower frequency 
and a larger size projector with acoustic power 
output up to the resulting cavitation limit, 
which give maximum ranges roughly twice as 
large as present searchlight gear.^^® 

The coverage rate obtainable with scanning 
sonar for a given maximum range will, in gen- 
eral, be considerably greater than that obtain- 
able with searchlight gear. This conclusion is a 
consequence of the simultaneous insonification 
by the scanning sonar beam of the whole 360° 
horizontal section resulting essentially in the 
detection of all targets within the maximum 
range ; with searchlight gear, on the other hand, 
because of the relatively narrow beam and the 
time required to complete a full sweep, targets 
may not be detected even though within the 
maximum range. 

Coverage rates that may be expected with 
scanning sonar are given in this section. The 
coverage rate depends on the relative ship-sub 
velocity v, on the maximum range r^ax, on the 


judged range i.e., on the interval T be- 
tween successive pings, (ry = cT/2), and on the 
shape of the detection probability versus range 
curve. The latter is taken as (see Figure 156) 

p(r) = /i = 2, 4, oo , 

where p(r) is the probability of detecting a 
sub at range r, and the constant ro is determined 
by the fact that 

P(^max) ~ 0.50, 

that is, the probability of detection at the maxi- 
mum range is just 50 per cent. In practice, the 
shape of the detection probability versus range 
curve is determined by the variation of both 
signal and background with ranged i.e., mainly 
by attenuation conditions, and by a psychologi- 
cal curve relating the signal to background 
ratio and the probability of detection in per 
cent;^ computations indicate that the curve in 
Figure 156 with = 4 is in fair agreement with 
detection probability versus range curves ob- 
tained in practice.^ The curves in Figure 156 
with n — 2, n = ^ represent extreme cases of 
a long '‘tail’’ and no “tail” at all for the detec- 
tion probability ; it is obvious that a long “tail” 



Figure 157. Coverage rate for scanning sonar 
and searchlight gear. Ship speed = 15 knots. 

is useful in scanning sonar. This conclusion 
follows from the fact that in scanning sonar 
each target is pinged on a great many times be- 
cause of the 360° beam and so may have a 

^ See Figure 10 of reference 153. 

^ See Figures of reference 164. 

^ Compare the curve with w = 4 in Figure 156 with 
the detection probability versus range curve given in 
Figure 20 of reference 153. 


( fOXFIDENTIAL ^ 


SCANNING SONAR 


273 


resultant probability of detection which is not 
negligible even though the probability of de- 
tection per ping is very small. 

Figures 157 and 158 give coverage rates for 



Figure 158. Coverage rate for scanning sonar 
and searchlight gear. Ship speed = 25 knots. 

scanning sonar for ship-sub speeds of 15 knots 
and 25 knots as a function of ry/r^ax and for n = 
2, 4, and oo. The coverage rate C, and the search 
efficiency (e* = C/2r^^^v), obtained from these 
curves, using in each case the optimum value of 
the judged range, “ are shown in Table 2. 


Table 2 




15 knots 



25 knots 



n = 2 

« = 4 

W = 00 

n = 2 

w = 4 

w = 00 

c 

in square 
nautical 
miles per 
hour 

7 5rmax 

50/'jnax 


1 25rniax 

7 5rniax 


es 

250% 

160% 

100% 

250% 

150% 

100% 


In a similar way, the coverage rates of 
searchlight gear may be found. These coverage 

The optimum value of the judged range is, of 
course, the one which gives the greatest coverage rate 
for a given maximum range and ship-sub speed. See 
Figure 157. 


rates depend, in addition to the factors men- 
tioned above, (ry, r^ax, n, v) on the beam width 
which, for all present and proposed searchlight 
gear, corresponds to a directivity index of 
about — 23 db. Figures 157 and 158 also pre- 
sent coverage rates of searchlight gear for ship- 
sub speeds of 15 and 25 knots as a function of 
^/Amax and for n = 2, 4, oo (directivity index = 
— 23 db). The coverage rate and search effi- 
ciency values obtained from these curves, using 
in each case the optimum value of r^., are shown 
in Table 3. 


Table 3 




15 knots 



25 knots 



n = 2 

« = 4 

W = 00 

n = 2 

n = 4 

W = 00 

C 

in square 
nautical 
miles per 
hour 

40r max 

35/'max 

30 f max 

65^'max 

55/'niax 

SOfmax 

es 

135% 

115% 

100% 

130% 

110% 

100% 


If the maximum range is taken to be equal 
for scanning sonar and present searchlight 
gear, that is, ^ 3,000 yd in good oceanographic 
conditions, it is seen that the scanning sonar 
has a somewhat higher coverage rate than 
present searchlight gear. On the other hand, 
with searchlight sonar gear incorporating pro- 
posed improvements^^^ and expected to yield in 
good oceanographic conditions twice the above 
maximum range, the coverage rate values are 
twice those in Table 3. (The search efficiency 
values will be the same as in Table 3.) 

Thus the proposed improved searchlight gear 
has a greater coverage rate except in the long 
“tair' case, n = 2, as well as a much greater 
maximum range than the scanning sonar. These 
advantages in detection may, however, be bal- 
anced by the advantages of scanning sonar in 
the chase and attack. 

Conclusion 

It is seen from the above discussion that in 
A/S operations, scanning sonar is superior to 


274 


NDRC DIVISION 6.1 DESIGNS 


all searchlight gear, present and proposed, in 
the chase and in the attack. In detection, scan- 
ning sonar is superior to present searchlight 


gear, but is possibly inferior to a proposed 
searchlight gear capable of a maximum range 
twice that obtainable at present. 


.(fONFID’ 


Chapter 7 

INDUSTRIAL DESIGNS 


T he instruments designed or built by in- 
dustrial organizations under contract with 
the Navy or NDRC are described in this chap- 
ter. In many cases instruments were both 
designed and manufactured by the same manu- 
facturer, although some instruments were de- 
veloped by NDRC laboratories and manufac- 
tured by industrial companies. As a rule only 
devices calibrated by the USRL have been in- 
cluded. Many devices which have been included 
in other chapters- are merely referred to herein. 
The following organizations are covered in this 
chapter : Brush Development Company, Bell 
Telephone Laboratories, Submarine Signal 
Company, Radio Corporation of America, and 
General Electric Company. The QBG, manu- 
factured by the Freed Radio Corporation, is 
discussed in Section 2.7.18, and the tourmaline 
gauges made by Stanolind Oil and Gas Com- 
pany are covered in Section 6.7.3. The scanning 
sonar designed by Harvard University and 
manufactured by the Sangamo Electric Com- 
pany is described in Section 6.8.2. 

7 1 INSTRUMENTS DESIGNED AND MANU- 
FACTURED BY BRUSH DEVELOPMENT 
COMPANY 

All underwater acoustic instruments designed 
and manufactured by the Brush Development 
Company employ piezoelectric coupling. Most 
of them use X-cut Rochelle salt crystals, al- 
though some use ADP crystals, e.g., AX-128, 
AX-114A, and AX-50. Neither Rochelle salt 
nor ADP crystals has a volume piezoelectric 
effect of useful magnitude, that is, the open- 
circuit voltage is very small when the crystal is 
compressed in such a way as to change its 
volume. The volume is changed when a pres- 
sure acts on all faces of the crystal. In order 
to prevent the pressure from acting on all sides 
of the crystal, the pressure must be relieved 
on some faces. This is accomplished in most 
Brush designs by covering four sides of the 
crystal unit with Corprene. Of the other two 
sides, one usually is exposed as the active face 


and the other is covered by a mounting plate, 
but sometimes both sides are exposed in a 
double-face design (CIO, Cll). 

As the impedance of crystal units is high, 
there is a large loss in the signal intensity of 
hydrophones when long leads are attached di- 
rectly to the crystals (coupling loss), with 
consequent high electric noise and electric 
pickup. Several methods are used to reduce this 
loss and circuit noise. (1) Short leads from 
hydrophone to receiving equipment are used. 
This method, for example, is employed in the 
C49 and AX-47 hydrophones. (2) A trans- 
former is built into the hydrophone to step 
down the output impedance of the crystal so as 
to permit long cables to be used with the 
hydrophone. Examples of this construction 
method are C23 and C37 hydrophones. (3) A 
one- or two-stage preamplifier is used near the 
hydrophone, i.e., underwater, permitting use of 
short leads from the crystal. The low output 
impedance of the preamplifier then minimizes 
coupling loss. Usually the preamplifier is built 
into the hydrophone. This is done in C50 and 
AX-75 units. 

Some of the hydrophones intended for use as 
measurement standards, e.g., the CIO, include 
calibrating circuits for obtaining the open- 
circuit crystal response. 

Almost all the instruments are filled with 
castor oil to permit their use at depths of sev- 
eral hundred feet without collapse and to with- 
stand explosion shocks. Most of them are com- 
pletely enclosed in sound-transparent rubber, 
or at least the active face is rubber-covered. 
Important exceptions in both respects are the 
CIO and Cll hydrophones which are neither 
oil-filled nor rubber-covered. These hydro- 
phones, being intended for use as standards, 
are intended neither for use at considerable 
depth nor to be exposed to explosions. 

Various combinations and arrangements of 
crystal units have been employed to give par- 
ticular directivity patterns. Line hydrophones, 
such as the C37, which are nondirectional in a 
plane normal to the line and discriminate 


^CQNFIDE^TDt!^ 


275 


276 


INDUSTRIAL DESIGNS 


against sounds originating in a direction along 
the line, consist of several crystal units ar- 
ranged in a row and connected electrically in 
parallel. Nondirectional units, like the AX-79, 
consist of a single crystal unit. Dual-pattern 
hydrophones (C44, AX-6, AX-47) are essen- 
tially two hydrophones in one housing, one 
being directional and the other nondirectional. 
By connecting these two units opposing a dif- 
ferential hydrophone may then be obtained. 
Other special pattern devices have also been 
built. 

Any instrument which does not have a 
built-in preamplifier can be used as either a 
projector or a hydrophone. Both response 
curves are given here in many such cases, 
although the device is intended mainly for one 
or the other of these roles. Other units are in- 
tended only for transmitting sound, e.g., the 
AX-63 projector. 

Many preliminary and experimental models 
are mentioned in the descriptions of the final 
instrument. Several Brush designs have been 
used by the USRL as standards, for example, 
the Cll, C13, AX-91, and AX-124 units. A 
description of these devices will be found in 
Sections 1.4.17, 1.4.8, 1.4.13, and 1.4.2, respec- 
tively. The JO, JQ, Modified JQ, and AX-63 are 
to be found in Sections 2.7.2, 2.7.4, 2.7.5, and 
2.7.40, respectively. References to calibrations 
of Brush instruments in this chapter are to be 
found in Sections 7.6.1 to 7.6.16. 

7 2 INSTRUMENTS DESIGNED AND MANU- 
FACTURED BY BELL TELEPHONE 
LABORATORIES 

The work of the Bell Telephone Laboratories 
[BTL] in this war has been concerned with 
many aspects of the underwater sound field, as 
covered by contracts with both NDRC and the 
Navy. As discussed in Chapter 1, BTL have 
designed and constructed the majority of the 
standard hydrophones and projectors which 
have been used by the USRL and by other 
laboratories working in the field. The BTL 
built most of the electrical equipment for the 
USRL test stations.^ They designed Navy echo- 
ranging equipments, such as the QBF and the 

^ See STR Division 6, Volume 10. 


QJB systems, which were manufactured by the 
Western Electric Company for the Navy, and 
constructed various ordnance devices and ex- 
perimental sonar apparatus. In addition, they 
carried out a number of investigations in the 
underwater sound acoustical field. For instance, 
they made a study of listening systems for 
patrol craft, for which they developed various 
instrumentalities as well as acoustical designs. 

The USRL have assisted in many phases of 
this work through the calibration of devices 
but have by no means had contact with all of 
the activity of the BTL. Several of the Navy 
equipments developed by BTL are described in 
Chapter 2. In Sections 7.6.17 to 7.6.22 are given 
descriptions of a number of listening devices 
designed by BTL, such as the 4 A, 5 A, 7A, 8 A, 
and 9A hydrophones, and a nondirectional mag- 
netostriction hydrophone. In addition, there are 
described three projectors designed by BTL 
for the University of California, Division of 
War Research, at San Diego, for use in under- 
water sound transmission studies. (See Sec- 
tion 7.6.23.) 

7-3 INSTRUMENTS DESIGNED AND MANU- 
FACTURED BY SUBMARINE SIGNAL 
COMPANY 

The Submarine Signal Company [SSC] has 
a leading role in the production of underwater 
sound equipments for the U. S. Navy. The 
USRL has calibrated a number of transducers 
designed and manufactured by SSC for under- 
water use. 

Twenty-five of these transducers are de- 
scribed in Chapter 2. Of this number, 5 are 
magnetostrictive types used in echo-sounding 
equipment, 17 are used in echo-ranging equip- 
ment, of which 7 are the magnetostrictive type, 
3 use Rochelle salt crystals for the active ele- 
ments, and 7 are a combination of a magneto- 
striction unit and a Rochelle salt crystal unit, 
mounted back to back in the same housing. 
Three of the transducers tested are experi- 
mental units. One of these uses ADP crystals 
for its electroacoustic coupling, one is an elec- 
trodynamic type, and one consists of a mag- 
netostrictive type unit in a reflector-type 
housing. 


^NFIDENTiSlr-—; 


GE INSTRUMENTS 


277 


In addition to the transducers described in 
Chapter 2, the USRL calibrated two line hydro- 
phones. The SS-6 is a 6-ft line and the S-124 
is a 2-ft line. These hydrophones are described 
in Sections 7.6.25 and 7.6.24 respectively. 

7-4 INSTRUMENTS DESIGNED AND MANU- 
FACTURED BY THE RADIO CORPORA- 
TION OF AMERICA 

The instruments designed by The Radio Cor- 
poration of America [RCA] and tested by the 
USRL have employed all types of electro- 
acoustic coupling. The Electrodynamic hydro- 


manufactured in large quantities, but the other 
three were mainly experimental and prelimi- 
nary models. Other magnetostrictive and piezo- 
electric instruments have been manufactured 
by RCA in large quantities for Navy use and 
are discussed in Chapter 2. 


7 5 INSTRUMENTS DESIGNED AND MANU- 
FACTURED BY THE GENERAL 
ELECTRIC COMPANY 

Two types of General Electric Company 
[GE] instruments have been calibrated by the 


Submarine Signal Company Projectors Discussed in Chapter 2. 


Section 

U. S. Navy No. 

SSC No. 

Type 

Use 

2. 7. 10 

CBM 78016A 

551B 

M/S 

Sounding 

2. 7. 19 

CBM 78017 

550C 

M/S 

Echo ranging 

2. 7. 9 

CBM 78067 

763 

M/S 

Sounding 

2. 7. 20 

CBM 78099 

550L 

M/S 

Echo ranging 

2. 7. 24 

CBM 78115 

733F 

M/S-R/S 

Echo ranging — listening 

2. 7. 8 

CBM 78138 

713C 

M/S 

Sounding 

2. 7. 15 

CBM 78142 

865 

R/S 

Echo ranging — listening 

2. 7. 16 

CBM 78142A 

865A 

R/S 

“ “ 

2. 7. 27 

CBM 78145 

880 

M/S 

“ “ 

2. 7. 34 

CBM 78153 

733H 

M/S-R/S 

a a 

2. 7. 38 

CBM 78156 

885 

M/S-R/S 


2. 7. 28 

CBM 78164A 

900E 

M/S-R/S 

ti it 

2. 7. 23 

CBM 78182 

550V 

M/S 

it a 

2. 7. 21 

CBM 78183 

550W 

M/S 

it it 

2. 7. 25 

CBM 78184 

733K 

M/S-R/S 

it ti 

2. 7. 26 

CBM 78185 

733L 

M/S-R/S 

it it 

2. 7. 13 

CBM 78203 

943 

M/S 

Sounding 

2. 7. 35 

CBM 78212 

948 

M/S-R/S 

Echo ranging — listening 

2. 7. 36 

CBM 78213 

733R 

R/S 

Echo ranging 

2. 7. 14 

CBM 78214 

947 

M/S 

Sounding 

2. 7. 30 

CBM 78220 

941 

M/S 

Echo ranging 

2. 7. 31 

CBM 78221 

942 

M/S 

ii 

2. 7. 44 


SK 5982 

ADP 

Experimental 

2. 7. 48 


SK 4044 

Electrodynamic 

it 

2. 7. 49 


SK 4610C 

M/S-reflector 



phone (see Section 7.6.27), as the name implies, 
is an electromagnetic device. The Magneto- 
striction hydrophone (see Section 7.6.28) uses a 
magnetostrictive nickel rod as active element. 
The 2 A Condenser hydrophone (see Section 
7.6.26) employs electrostatic coupling. The 
USDAR (see Section 7.6.29) uses piezoelectric 
quartz crystal. All these types have worked 
satisfactorily, although the condenser type has 
not been widely used. The USDAR has been 


USRL (see Sections 7.6.30 and 7.6.31). The 
Carbon hydrophone, an early type adapted from 
the carbon air microphone was intended for use 
in a binaural listening system. Much later sev- 
eral high-frequency projectors used with the 
Underwater Object Locator were tested. These 
units employed L-cut Rochelle salt crystals and, 
due to the high frequencies (250, 750 kc) at 
which they operate, could be mounted on curved 
plates to obtain desired directivity patterns. 


^^NFIDENTIAL ^ 


278 


INDUSTRIAL DESIGNS 


7 6 INDUSTRIAL DESIGN INSTRUMENTS 


AX-47 and AX-47-1 Hydrophones 


Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. 6.1-sr20-610, March 9, 1943.^^^ 

Description: Both the AX-47 and AX-47-1 models contain a directional 
unit consisting of a circular crystal array and a centrally located non- 
directional crystal unit. A schematic diagram giving the approximate 
dimensions of the AX-47 hydrophone is shown in Figure 4. The AX-47-1 
model is similar to the AX-47. The operation is similar to that of the C44 
described in Section 7.6.14. 

Impedance in ohms: 


Frequency Directional unit Nondirectional unit 

(kc) R X R X 


10.0 

30,200 — i317,000 

20,100 — y317,000 

20.0 

39,800 — il37,000 

29,500 — yi54,000 

22.5 

27,600 — illl,300 

21,500 — il38,200 

25.0 

36,200 — j 91,600 

25,500 — j 99,600 

30.0 

48,000 — j 52,600 

42,400 — j 71,000 

40.0 

109,000 — j 32,400 

81,200 — j 27,600 

50.0 

106,200 — il09,500 

137,000 — j 78,200 

Threshold in db vs 1 dyne per sq cm : 


Frequency 

Directional unit 

Nondirectional unit 

(kc) 



10 

—81.6 

—73.8 

20 

—79.1 

—65.1 

25 

—82.9 

—70.9 

25 

—81.3 

—75.0 

30 

—86.0 

—73.6 

40 

—81.1 

—74.7 

50 

—79.6 

—74.1 


^tidentTaI^ 


INDUSTRIAL DESIGN INSTRUMENTS 


279 



J80* 


Figure 1. Directivity pattern, AX-47 hydro- 
phone at 20 kc, response of nondirectional unit 
reduced 5 db below that of directional unit. 


5o 

— cn 


5^3 


So 


-60 

-70 

-80 

-90 

-100 


uj (r 

o 
o u. 


NON-DIRECTIONAL 


UNIT. 






DIRECTIONAL UNIT 


% 


ft 




10 100 
FREQUENCY IN KC 


Figure 2. Receiving response, AX-47 hydro- 
phone measured at output of coupling trans- 
former. 



Figure 3. AX-47 hydrophone with diaphragm 
removed. 



Figure 4. Dimensional drawing, AX-47 hydro- 
phone. 


^E®ENTIAL 


280 


INDUSTRIAL DESIGNS 


AX-50 Hydrophone 


Type: ADP Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. 6.1-sr20-1181, October 22, 1943.205 

Use: Listening unit intended for sono buoy. 

Description: The ADP crystal is mounted in a rubber-covered, oil- 
filled, cylindrical housing similar to that of the C23, C50, and other Brush 
models. The unit contains a built-in one-stage preamplifier which uses a 
1LN5 tube (see circuit schematic diagram). The device is nondirectional 
from 1 kc up to about 30 kc. 



Figure 5. Directivity patterns, AX-50 hydro- Figure 6. Directivity patterns, AX-50 hydro- 
phone in plane containing long axis. phone in plane normal to long axis. 


INDUSTRIAL DESIGN INSTRUMENTS 


281 




Figure 7. Receiving response, AX-50 hydro- 
phone. Figure 8. Measured threshold, AX-50 hydro- 

phone. 




Figure 9. AX-50 hydrophone. 



Figure 10. Dimensional drawing, AX-50 hydro- 
phone and preamplifier circuit. 


I 



282 


INDUSTRIAL DESIGNS 


AX-58A (RQ-5I055) Hydrophone 

Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. 6.1-sr20-949, August 17, 1943.^^2 

Use: With portable measuring equipment. 

Description: The AX-58 A is a slight modification of the AX-58 which it 
replaces. It is similar in appearance to the C50. The photograph shows 
the unit with the rubber cover removed. 

It is approximately 26 in. in length and 2.5 in. in diameter. A 3-in. 
crystal block is mounted at one end and surrounded by a sound window. 
At the other end there is space for two stages of amplification which is to 
be furnished by the user. This instrument was widely used by the Navy 
in portable measuring equipment, especially for measuring and monitor- 
ing submarine noise output. 



180 


Figure 11. Directivity patterns, AX-58A hydro- 
phone in plane containing long axis. 


INDUSTRIAL DESIGN INSTRUMENTS 


283 



frequency in kc 


Figure 12. Receiving response, AX-58A hydro- 
phone. 



Figure 15. AX-58A hydrophone with rubber 
cover removed. 



Figure 13. Temperature variation of receiving 
response, AX-58A hydrophone. 



.1 I 10 

FREQUENCY IN KC 

Figure 14. Measured threshold, AX-58A hydro- 
phone. 



Figure 16. Dimensional drawing, AX-58A 
hydrophone. 



284 


INDUSTRIAL DESIGNS 


7 . 6.4 


AX-63 Projector 


Type: ADP Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. 6.1-srll30-1187, November 16, 1943.^® 

Use: Echo ranging (experimental model). 

Description: The instrument is cylindrical in shape, 14 in. in diameter 
and 5 in. in length. The crystals, ADP, are mounted on a glass plate. A 
•ys-in. thick rubber diaphragm forms the front face and the space between 
the diaphragm and crystal block is oil-filled. The measurements were 
made at the terminals of a 20-ft cable attached to the instrument. 

Impedance in ohms: 


Frequency 

(kc) 


Parallel tuning 


Series tuning 


23.0 
24.2 

25.0 


4970 — j 967 
4780 — il005 
5880 — il015 


181 — i933 
202 — i963 
170 — i987 


Threshold in db vs 1 dyne per sq cm : 


Frequency 

(kc) 


Parallel tuning 


Series tuning 


23.0 
24.2 

25.0 


—87.0 

—89.9 

—86.5 


—101.4 

—103.6 

—101.7 


Transmitting 


Efficiency: Approximately — 2 db at resonance. 


( ^FIDENTIAL i/ 


INDUSTRIAL DESIGN INSTRUMENTS 


285 



ISO* 

Figure 17. Directivity pattern, 
jector at 24.2 kc. 


AX-63 pro- 



Figure 19. Receiving response, AX-63 pro- 
jector. 



Figure 18. Transmitting response, AX-63 pro- 
jector. 



Figure 20. AX-63 projector. 





CONFIDENTIAI^ ] 


286 


INDUSTRIAL DESIGNS 


" ^ " AX.79, AX.79-1 Hydrophones 

Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

Use: Intended as sound pressure indicator inside a tank. 

Description: The AX-79 and AX-79-1 are similar in construction and 
appearance but AX-79-1 is the slightly larger of the two, being about 6 in. 
long while AX-79 is only 4 in. long. Other dimensions are in proportion 
to the length. The crystals are cemented to a backing plate and enclosed 
in a sound-transparent rubber cover. The space between rubber and 
crystals is oil-filled. The housing incorporates a mounting fiange to per- 
mit attachment to a tank. The unit is fairly nondirectional up to about 
28 kc. 

Efficiency: — 3.5 db (for 150-db available power) at 26 kc. 

Threshold: — 91.4 db vs 1 dyne per sq cm at 26 kc. 



180 * 


Figure 21. Directivity pattern, AX-79-1 trans- 
ducer in plane containing short axis. 



Figure 22. Directivity pattern, AX-79-1 trans- 
ducer in plane containing long axis. 


P P^;fidential ^ 


THRESHOLD PRESSURE PRESSURE AT I METER IN OB VS I DYNE /SO CM 

IN DB VS I DYNE/SQCM PER WATT AVAILABLE POWER FROM i35 OHMS 


INDUSTRIAL DESIGN INSTRUMENTS 


287 



Figure 23. Transmitting response, AX-79-1 
;ransducer. 



Figure 24. Receiving response, AX-79-1 trans- 
ducer. 



I 10 100 

FREQUENCY IN KC 


Figure 25. Threshold, AX-79-1 transducer. 



Figure 26. Impedance, AX-79-1 transducer. 



Figure 27. AX-79-1 transducer. 

Ctonfide^al I 


288 


IM)USTRIAL DESIGNS 


AX-83 Hydrophone 
Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer: Brush Development Company. 

Use: Measurement standard. 

Description: The AX-83 is similar in size, appearance, and mechanical 
construction to the C23. The crj^stal unit is near the middle of a 2.5 in. 
diameter, oil-filled, rubber-covered tube, the overall length of the device 
being about 14 in. It is nondirectional up to about 30 kc. 


o* 



Figure 28. Directivity pattern, AX-83 trans- 
ducer at 15 kc. 




INDUSTRIAL DESIGN INSTRUMENTS 


289 



Figure 29. Transmitting response, AX-83 
transducer. 



Figure 30. Receiving response, AX-83 trans- 
ducer. 



Figure 31. Calculated threshold, AX-83 trans- 
ducer. 



Figuue 32. Impedance, AX-83 transducer. 



Figure 33. AX-83 transducer. 



REACTANCE- OHMS 


290 


EST)USTRL\L DESIGNS 


AX-114A Hydrophone 


Ttfpe: ADP Crystal. 

Designer and Manufacturer: Brush Development Comi)any. 

Use: Subsonic listening unit for mines. 

Description: The ADP crystals in this hydrophone are mounted on a 
metal plate and have a diaphragm in front of them. The space between 
the diaphragm and the rubber cover is oil-filled. The housing incorporates 
a mounting flange. 


INDUSTMAL DESIGN ESSTRUNIENTS 


291 



2 ^ 
§1 


0)3 QJ I O 100 

FREOUCMCT m KC 

Figube 34. Receiving response, AX-114A hydro- 
phone. 



Figube 3o. AX-114A hydrophone. 


292 


INDUSTRIAL DESIGNS 


AX-128 Transducer 


Type: ADP Crystal. 

Designer and Manufacturer : Brush Development Company. 

Use: For practice target. 

Description: The AX-128 transducer can be used as either hydrophone 
or projector in the 20- to 30-kc range. It is approximately nondirectional 
in a plane normal to the transducer axis, but somewhat directional in a 
plane containing this axis. It is about 3 in. in diameter, 11 in. in length, 
rubber-covered and oil-filled. 



ISO 


Figure 36. Directivity pattern, AX-128 trans- 
ducer at 25 kc in plane normal to axis. 



Figure 37. Directivity pattern, AX-128 trans- 
ducer at 25 kc in plane containing axis. 





INDUSTRIAL DESIGN INSTRUMENTS 


293 



Figure 38;* Transmitting response, AX-128 
transducer. 



Figure 39. Receiving response, AX-128 trans- 
ducer. 


r 

M a 

UJ o 


-100 

-90 

-80 

-70 




10 

FREQUENCY IN KC 


100 


Figure 40. Threshold, AX-128 transducer. 



10 20 30 40 

FREQUENCY IN KC 

Figure 41. Impedance, AX-128 transducer. 


-IX 10^ 


-2 




-7 




294 


INDUSTRIAL DESIGNS 


7 . 6.9 


AX-I3I Transducer 


Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

Use: Scanning transducer for testing materials. 

Description: The AX-131 is a high-frequency transducer designed for 
use in the region of 400 kc. It is oil-filled with a rubber cover over the 
active face. The overall length of the device is about 5 in. and the diameter 
of the face about 2 in. The radiating area is rectangular and about 1.5 in. 
long by 1 in. wide. 



INDUSTRIAL DESIGN INSTRUMENTS 


295 



Figure 43. Directivity patterns, AX-131 trans- 
ducer in plane containing: axis and long dimen- 
sion of crystal unit. 



Figure 44. Transmitting response, AX-131 
transducer. 



Figure 45. Receiving response, AX-131 trans- 
ducer. 



Figure 46. Calculated threshold, AX-131 trans- 
ducer. 





Figure 48. AX-131 transducer. 



296 


INDUSTRIAL DESIGNS 


CIO Hydrophone 

Type: X-Cut Quartz Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. C4-sr20-148, July 27, 1942.® 

Use: Measurement standard. 

Description: This instrument has the same dimensions as the Cll-Al 
standard hydrophone described in Chapter 1, except that the diameter of 
the pickup head is in. It contains a built-in preamplifier and calibra- 
tion circuit. The preamplifier is operated from dry cells and the unit is 
supplied with 28 ft of 5-conductor cable. 


INDUSTRIAL DESIGN INSTRUMENTS 


297 


/ 



1.0 10 FREQUENCY IN KC I00 


Figure 49. Receiving response, CIO hydrophone. 



Figure 50. CIO hydrophone. 


OyFIDENTlA^) 


298 


INDUSTRIAL DESIGNS 


^ C23 Hydrophone 

Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. C4-sr20-298, November 20, 1942. 

Use: High-pressure measurements. 

Description: A heavy cylindrical rubber body 15 in. long and 2.5 in. 
in diameter contains the crystals Avhich are immersed in oil. A 1.75-in. 
wide metal band around the body adds mechanical strength. The unit also 
contains, as an integral part, a step-down transformer from which the 
output is taken. The output impedance of the unit is, therefore, low enough 
to permit use of long cables without appreciable coupling loss. The data 
given were measured at the end of a 25-ft cable. A response measurement 
which was made across the secondary of a special grid transformer at the 
end of the cable is also shown. 

This instrument replaced Brush model XEl. 



Figure 51. Directivity patterns, C23 hydro- 
phone in a plane normal to axis. 


^ONnUKXTIAL ^ 


INDUSTRIAL DESIGN INSTRUMENTS 


299 



Figure 52. .Receiving response, C23 hydrophone 
measured at cable terminals. 




Figure 53. Receiving response, C23 hydrophone 
measured across secondary of transformer at 
end of cable. 



phone. 





Figure 56. C23 hydrophone. 


A' 


95' OF RUBBER 
COVERED CABLE 



Figure 57. Dimensional drawing, C23 hydro- 
phone. 


300 


INDUSTRIAL DESIGNS 


C37 Hydrophone 

Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. C4-sr20-286, October 5, 1942.^^2 

Use: Listening, harbor defense. 

Description: The C37 is a line hydrophone 4.5 ft long. It consists of 
eight C23 crystal units arranged in a line in a rubber-covered, oil-filled 
tube. The units are connected in parallel. A built-in transformer permits 
the use of several hundred feet of cable v^fith the device. It is essentially 
nondirectional in a plane normal to its axis. The preproduction model was 
the AX-10. The C37-5 and C37-6 differ slightly from C37 in mechanical 
details. The main difference is in the rubber cover which is po, rubber in 
the C37 and ordinary rubber in the other two. The C37-5 is a towing 
hydrophone and the C37-6 is used for harbor defense. 



Figure 58. Directivity pattern, C37 hydro- 
phone at 12 kc. 


infid: 



INDUSTRIAL DESIGN INSTRUMENTS 


301 



Figure 59. • -Receiving response, C37 hydrophone 
measured at cable terminals. 



Figure 62. Impedance, C37 hydrophone. 


)B VS 1 VOLT 

1 DYNE /SO CM 

i 







































































































































1 

1 



OPEN CIRCUIT VOLTS IN C 
FOR A SOUND FIELD OF 1 
' ' 

O O C 






















































5 ^ 




































































































































OJ I FREQUENCY IN KC K) 


Figure 60. Receiving response, C37 hydrophone 
measured at output of coupling transformer. 


z 

-or 

§ o 
w W 

W 

kj u 

CC Z •QO 

































































































































































































Q, > OU 

o 

o > -70 

w a 
wo 

































































































p 5 "IKJ 


















































.1 I 10 


FREQUENCY IN KC 

Figure 61. Calculated threshold, C37 hydrO' 
phone. 



Figure 63. C37 hydrophone. 



Dimensional drawing, C37 hydro- 


Figure 64, 
phone. 


^ ^^^.\FIDENTIAU> 


302 


INDUSTRIAL DESIGNS 


7 . 6.13 


C43 Hydrophone 


Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. 6.1-sr20-871, May 14, 1943.^^^ 

Use: With expendable radio sono buoy. 

Description: The crystals are mounted in an oil-filled steel, cylindrical, 
tubular container covered with sound-transparent rubber. The overall 
length is 8.5 in. The leads in a single rubber-covered cable are brought out 
through a hemispherical metal cap at the end of the unit farthest from the 
crystal assembly. 



iNFIDExV 


INDUSTRIAL DESIGN INSTRUMENTS 


303 



FREQUENCY IN KC 

Figure 65. Receiving response, C43 hydrophone. 


0 

I 

-2or 


uis -40 
o: o 



0.1 I 10 100 

FREQUENCY IN KC 


Figure 66. Calculated threshold, C43 hydro- 
phone. 



Figure 67. Impedance, C43 hydrophone. 



Figure 68. C43 hydrophone. 



Figure 69. Dimensional drawing, C43 hydro- 
phone. 


304 


INDUSTRIAL DESIGNS 


" C44, AX-6, AX-6-F Hydrophones 

Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

References: NDRC Report No. C4-sr20-285, September 30, 1942.1®^ 
NDRC Report No. C4-sr20-299, November 26, 1942.^®^ 

Description: The C44, AX-6, and AX-6-F instruments are the same in 
appearance. They are contained in a cylindrical housing 2 V 2 in. in diameter 
by approximately 16 in. in length, covered with sound-transparent rubber. 
This housing is similar to that used for the C23 type hydrophone. (See 
photograph and drawing of C23, Figures 56 and 57.) Each dual-pattern 
hydrophone consists of three units of X-cut Rochelle salt crystals, which 
are arranged along the hydrophone axis. Two of the units, each approxi- 
mately 2 in. long, are connected in parallel and comprise the directional 
array of the hydrophone. The other unit functions by itself and gives a 
pattern which is essentially nondirectional. In the C44 hydrophone the 
spacing between the centers of the units used in the directional array is 
about 5 in., in the AX-6 about 4 in., and slightly less in the AX-6-F. The 
nondirectional unit is smaller than the array units. In the AX-6 hydro- 
phone the nondirectional unit is located at the end of the hydrophone 
farthest from the leads. In the C44 hydrophone it is located between 
the two elements of the directional unit. 

Each hydrophone contains two step-down transformers, one for the 
nondirectional unit and the other for the array units. 

The dual-pattern hydrophone system depends for its operation on the 
relative response of the array and of the separate unit. Operation of the 
associated electric system occurs when the output of the array exceeds 
that of the separate unit. Amplifiers with suitable gains are used in the 
output circuits to provide this relation over the desired angular range. 
The reliability of operation of the system for different angular positions 
of the hydrophone with respect to the direction of sound incidence then 
depends on the difference in directivity of the array and that of the 
separate unit. 

The data shown are for a C44, but the other instruments do not differ 
appreciably. 

Impedance in ohms : 


F requency 
(kc) 

Directional 

unit 

Nondirectional 

unit 

1 

6.5 — i41.4 

32.1 — yi54.0 

5 

5.2 + j 0.15 

5.3 — j 21.4 

7 

5.0 + j 5.7 

5.0 — j 10.1 

8 

5.1 + j 8.4 

5.0 — j 6.2 

9 

5.3 + ilO.7 

5.3 — j 2.5 

15 

5.5 + i23.1 

4.8 + j 13.4 




INDUSTRIAL DESIGN INSTRUMENTS 


305 



90* 


180 '^ 


Figure 70. Directivity patterns, C44 hydro- 
phone at 8 kc. 




i) 


306 


INDUSTRIAL DESIGNS 


C49 Hydrophone 

Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. 6.1-sr20-1185, November 12, 1943.21^ 

Use: Acoustic mines. 

Description: The four crystal assemblies are cemented to the back of 
the metal case and the sides of each assembly are covered with Corprene. 
The housing is oil-filled, covered with a metal diaphragm and enclosed by 
a rubber cover. The hydrophone is nondirectional up to at least 15 kc. 



Figure 72. Directivity pattern, C49 transducer 
at 6.65 kc. 


fONFID®: 


INDUSTRIAL DESIGN INSTRUMENTS 


307 




Figure 76. Impedance, C49 transducer. 


Figure 73. ^Transmitting response, C49 trans- 
ducer. 



Figure 74. Receiving response, C49 transducer. 



Figure 77. C49 transducer with crystals ex- 

posed. 




Figure 75. 
ducer. 


Calculated threshold, C49 trans- 


Figure 78. 
ducer. 


/CDN’FmENfLAjj) 


Dimensional drawing, C49 trans- 


lOloO 


308 


INDUSTRIAL DESIGNS 


7 . 6.16 


C50 Hydrophone 


Type: X-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : Brush Development Company. 

Reference: NDRC Report No. 6.1-sr20-880, June 19, 1943.^®" 

Use: Measurement standard. 

Description: The crystal assembly and preamplifier are contained in a 
cylindrical metal tube covered 'with sound-transparent rubber. Around the 
crystal is a sound 'window approximately 1.5 in. long. A 10-ohm calibrating 
resistor is included to permit measurement of the open-circuit crystal 
voltage. Calibrating leads, preamplifier output leads, and preamplifier 
supply voltage leads are brought out in a single cable. The device is non- 
directional in a plane normal to the axis. 



INDUSTRIAL DESIGN INSTRUMENTS 


309 



Figure 79. Directivity pattern, C50 hydro- 
phone. 



Figure 80. Receiving response, C50 hydrophone. 




FREQUENCY IN KC 


Figure 82. Voltage gain of preamplifier, C50 
hydrophone. 



Figure 83. Preamplifier circuit, C50 hydro- 
phone. 



Figure 84. Dimensional drawing, C50 hydro- 
Figure 81. C50 hydrophone. phone. 




310 


INDUSTRIAL DESIGNS 


4A Cable Hydrophone 


Type: Electromagnetic. 

Designer: Bell Telephone Laboratories. 

Reference: NDRC Report No. 6.1-sr692-661, December 15, 1942.^^^ 

Use: Harbor protection. 

Description: The essential structure of the sound element is shown in 
the cross section. A and B are permanent magnets which supply the 
magnetomotive force for the magnetic circuit. C and D are soft iron pole 
pieces, bent into horseshoe shape, which support the coil. The unit is 
mounted in a brass tube and fitted into the envelope of a standard all-metal 
radio tube which is then sealed and imbedded in a rubber cover. 

The basic structure has been used in the design of several other models 
containing one or more units combined in a suitable housing to obtain 
either a pressure or pressure gradient response with a circular, figure- 
eight, cardioid, or toroidal directivity pattern. 



OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF I DYNE/SQ CM 


INDUSTRIAL DESIGN INSTRUMENTS 


311 



Figure 85. Directivity patterns, 4A cable hydro- 
phone. 



100 1,000 10,000 
FREQUENCY IN KC 



Figure 87. Impedance, 4A cable hydrophone. 



Figure 88. 4A cable hydrophone. 




■ ■ — 

U 


A 

c 

a 


Figure 86. Receiving response, 4A cable hydro- 
phone. 


Figure 89. Cross section, 4A cable hydro- 
phone. 






312 


INDUSTRIAL DESIGNS 


5A and 5B Hydrophones 

Type: X-Cut Rochelle Salt Crystal. 

Operating range: Audio frequency. 

References: NDRC Report No. C4-sr20-297, November 16, 1942.^^^’ 
NDRC Report No. 6.1-sr692-1698, December 1, 1944.221 

Description: The 5 A and 5B hydrophones were experimental designs 
used in the study of listening systems for patrol craft carried on by BTL 
on NDRC contract. In these tests, the units were employed individually 
and in arrays consisting of six hydrophones spaced 6 in. apart, or approxi- 
mately % wavelength at 5 kc. The coupling amplifier used with the 5A 
hydrophone to provide a low impedance output is replaced in the 5B 
hydrophone by a transformer. 

The 5A and 5B hydrophones are predecessors of the 5C and 5E hydro- 
phones, which have been used as standards by the USRL (see Section 
1.4.16). 


INDUSTRIAL DESIGN INSTRUMENTS 


313 



180 ^ 


Figure 90. Directivity pattern, 5A hydrophone 
at 5 kc. 




Figure 92. 5A hydrophone. 


Figure 93. 5B hydrophone. 


Q 


mAh- «) 



314 


INDUSTRIAL DESIGNS 


7 . 6.19 


7A Hydrophone 


Type: X-Cut Rochelle Salt Crystal. 

Designer: Bell Telephone Laboratories. 

Reference: NDRC Report No. 6.1-sr692-1698, December 1, 1944.^21 

Use: For supersonic listening from patrol craft. 

Description: The 7 A hydrophone is an experimental design used in the 
study of an electrically steered supersonic listening system for patrol 
craft carried on by BTL on NDRC contract. The supersonic array con- 
sisted of two assemblies of Rochelle salt crystal hydrophones. Each hydro- 
phone employed a crystal block 0.7 in. square, mounted on a heavy steel 
resonator and covered with a diaphragm 1x2 1/^ in. Except for the size, 
the construction is very similar to that of the 5-type hydrophone. Nine of 
these crystal elements, each with its own diaphragm, were assembled in a 
bronze casting. 



INDUSTRIAL DESIGN INSTRUMENTS 


315 



^^NFIDENTIAL 


316 


INDUSTRIAL DESIGNS 


7 . 6.20 


8A Hydrophone 


Type: Electromagnetic, Pressure Gradient. 

Designer: Bell Telephone Laboratories. 

Use: With practice attack meter. 

Description: The assembly consists of four electromagnetic, inertia type 
units, similar to the element in the 4A hydrophone (see Section 7.6.17), 
mounted inside a spherical aluminum shell. The sphere and lead wires are 
vulcanized in rubber. A square steel bar is clamped within the sphere along 
a diameter, and to each of its four faces is fastened a soft iron armature. 
The 4A units are then suspended by a flat spring to the armatures. 

The theory of operation is as follows : The comparatively heavy magnet 
assembly remains motionless, while the sphere and armatures move with 
the pressure gradient in the sound field. Opposing units are connected in 
series, each pair giving a figure-eight, or cosine, pattern. The sign of the 
voltage generated depends on the direction in which the armature moves 
from its rest position. Thus for sound incident at the angle 6 in the 
explanatory diagram the voltage developed will be proportional to +A and 
-f R. For the reverse directions the voltages are — A and — B. Hence the 
direction of the incoming signal of the explosive wave is indicated without 
ambiguity. 



INDUSTRIAL DESIGN INSTRUMENTS 


317 



Figure 95. Receiving response, 8A hydrophone. 




Figure 96. 8A hydrophone. 



Figure 98. Explanatory diagram of operation, 
8A hydrophone. 




318 


INDUSTRIAL DESIGNS 


9A Hydrophone 

Type: Electromagnetic, Pressure Gradient. 

Designer: Bell Telephone Laboratories. 

Reference: NDRC Report No. 6.1-sr692-1698, December 1, 1944.221 

Use: Listening from small patrol boats. 

Description: The 9 A hydrophone is similar to the 8 A pressure gradient 
hydrophone (see Section 7.6.20) employing two 4A units (see Section 
7.6.17) enclosed in a spherical shell. The distinguishing feature is that an 
air space is enclosed in the rubber covering, which results in a cardioid 
form of directivity pattern. A brass-lined, watertight air cell and the butyl 
rubber covering cause a phase shift between sound at the front and back 
of the hydrophone, producing a cardioid directivity pattern. 


% /conitdknTBUL — fj 


INDUSTRIAL DESIGN INSTRUMENTS 


319 


90 * 



90 * 


180 ’ 


Figure 99. Directivity pattern, 9A hydrophone. 



Figure 101. 9A hydrophone. 




AIR CHAMBER 


Figure 102. Section of 9A hydrophone. 


J^FIDENT] 




320 


INDUSTRIAL DESIGNS 


7.6.22 Nondirectional Magnetostriction Transducer 

Type: Magnetostriction. 

Designer: Bell Telephone Laboratories. 

Reference: NDRC Report No. 6.1-srl097-1328, February 1, 1945.^24 

Use: To establish a uniform sound field in all directions. 

Description: A magnetostriction transducer developed by BTL which 
transmits a 24-kc signal approximately uniform in all directions. This 
uses a ring oscillator of nickel, operating on its remanent flux, and vibrat- 
ing in its fundamental radial mode. 


^xfidentialT^ 


INDUSTRIAL DESIGN INSTRUMENTS 


321 



,N0.28 enamel 
SILK WIRE 



RUBBER TUBING 


RING- 2 MIL SPIRALiy 
WOUND PERMALLOY 
TAPE 


ADJUSTING SCREW HoP 


Figure 103. Nondirectional magnetostriction 
transducer. 



322 


INDUSTRIAL DESIGNS 


7 . 6.23 


10 kc, 20 kc, and 40 kc Transceiver Units 


Type: 45° Y-Cut Rochelle Salt Crystal. 

Designer: Bell Telephone Laboratories. 

References: NDRC Report No. C4-sr20-592, December 10, 1942.^®® 


NDRC Report No. 6.1-sr20-613, March 29, 1943.194 


Use: For use in underwater sound transmission tests. 

Description: A group of transceivers was constructed for the University 
of California, Division of War Research at San Diego having essentially 
the same directivity at their operating frequencies, namely 10. 20, and 
40 kc. 

Each unit consists of blocks of wavelength Y-cut Rochelle salt crystals. 
These crystal blocks are backed by lead resonators and immersed in castor 
oil. A sound-transparent rubber cover encloses the assembly. To reduce 
side lobes, the crystal blocks on the ends of the array have been given 
double the thickness of the others. In order that all units may have the 
same directivity, the linear dimensions of the crystal faces are reduced 
directly proportional to the wavelengths at which they operate, as shown 
in the following table. 


Frequency 


Total crystal face 


10 c 
20 c 
40 c 


1364 sq cm 
371 sq cm 
92.9 sq cm 


The beams in the long axis have an angular width of about ±7V2°» 
and in the short axis an angular width of about ±35°. The units were 
designed to operate with inputs up to 250 w. At their resonant frequencies, 
these units are only about 1 db below the ideal in efficiency. 


.{CONFIDENTIAL 


INDUSTRIAL DESIGN INSTRUMENTS 


323 



^SHORT AXIS 

\ / >. / V 


Figure 104. Directivity patterns, 10 kc trans- 
ceiver unit No. 1 at 10.4 kc. 



Figure 107. Impedance, 10 kc transceiver unit 
No. 1. 



Figure 105. Transmitting response, 10 kc 
transceiver unit No. 1. 



Figure 106. Receiving response, 10 kc trans- 
ceiver unit No. 1. 




TRANSFORMER 
MOUNTED HERE 


Figure 108. 10 kc transceiver unit No. 1. 





\ 


FOR A SOUND FIELD OF I DYNE /SO CM 


324 


INDUSTRIAL DESIGNS 


S-124 Hydrophone 

Type: Rochelle Salt Crystal — 2-ft Line Hydrophone. 

Designer and Manufacturer: Submarine Signal Company. 

Reference: NDRC Report No. C4-sr20-144, July 13, 1942.^"^ 

Application: Underwater sound measurement in frequency range up to 
40 kc. 

Description: The S-124 hydrophone consists of a number of Rochelle 
salt crystal units in an aluminum housing 2 ft long with a 2 in. square 
cross section. Acoustic windows in the form of circular holes Ys in. in 
diameter are distributed over about 19 in. of the length of the hydrophone. 
Thirteen of these holes are in each of two opposite sides of the hydrophone. 
The capacity of the crystals, including a 25-ft length of 2-conductor 
rubber-covered cord is 2,300 /x/xf. 

Measured Impedance: 

at 1 kc = 1490 — ;21500 ohms 
at 5 kc = 268 — ;4430 ohms 
at 20 kc = 121 — ;904 ohms 



FREQUENCY IN KC 


Figure 109. Receiving response, S-124 hydro- 
phone. 


FOUR RODS- 
TIREX CORD-^i^ 


ACTIVE FACE 
IS 19" LONG 


CENTER OF 
ACTIVE 
ELEMENT 
(WINDOW it?) 


Figure 110. 



LORO, MOUNTINGS 


ALUMINUM HOUSING 

13 WINDOWS |‘diA. ON 

EACH OF TWO FACES 
(ISO® OPPOSED) 


PLAIN WINDOWS 
SQUARE 

WINDOWS WITH RINGS 

S-124 hydrophone. 


OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF I DYNE /SO CM 


INDUSTRIAL DESIGN INSTRUMENTS 


325 


SS-6 Hydrophone 

Type: Rochelle Salt Crystal — 6-ft. Line Hydrophone. 

Designer and Manufacturer : Submarine Signal Company. 

Reference: NDRC Report No. C4-sr20-144, July 13, 1942.^^^ 

Application: Underwater sound measurements in audio frequency range. 

Description: The SS-6 hydrophone consists of a number of Rochelle salt 
crystal units in a steel housing approximately 6 ft long with a 2-in. square 
cross section. An acoustic window in the form of a slit % in. wide and 
about 63 in. long is in the side of the housing just over the crystal units. 
The capacity of the crystals, including a 30-ft length of coaxial cable, is 
6,900 ju/Ltf. 

Measured Impedance: 

at 1 kc = 414 — y4600 ohms 
at 5 kc = 165 — ^825 ohms 
at 10 kc = 69.7 — ;617 ohms 



Figure 111. 
phone. 


Receiving response, SS-6 hydro- 



Figure 112. SS-6 hydrophone. 


lOXFIDE? 


1 


326 


INDUSTRIAL DESIGNS 


2A Condenser Hydrophone 
Type: Electrostatic (condenser). 

Designer and Manufacturer : Radio Corporation of America. 

Reference: NDRC Report No. C4-sr20-291, October 27, 1942.^*^ 
Description: The 2 A is a condenser transmitter type. The cylindrical 
housing has approximately a 17-in. overall length and 6-in. diameter. It 
contains a two-stage preamplifier which is designed to work into a load 
impedance of 500 ohms. A 6-conductor cable attached to the unit provides 
the supply voltages to the preamplifier and carries the output leads and 
calibrating leads. 


OPEN CIRCUIT VOLTS IN OB VS I VOLT 
FOR A SOUND FIELD OF I DYNE /SO CM 


INDUSTRIAL DESIGN INSTRUMENTS 


327 




Figure 113. Receiving response, 2 A condenser 
hydrophone. 


Figure 114. Receiving response, 2A condenser 
hydrophone, not including preamplifier. 




V 


328 


INDUSTRIAL DESIGNS 


RCA Electrodynamic Hydrophone 
Type: Electrodynamic. 

Designer and Manufacturer : Radio Corporation of America. 

References: USRL Orlando Project No. 17, March 4, 1944. 

See also, ‘‘Calibrated Subaqueous Microphones,’’ H. F. Olson 
and J. Preston, RCA Laboratories, October 26, 1943.2®^ 
Use: Standard for calibration measurements. 

Description: This instrument is of simple construction. The diaphragm 
is a YiQ-in. thick dome-shaped steel shell and it is coupled to a movable 
coil located in a magnetic field. 

Threshold: — 57 db vs 1 dyne per sq cm at 20 kc. 



INDUSTRIAL DESIGN INSTRUMENTS 


329 



FREQUENCY IN KC 

Figure 116. Receiving response, electro- 
dynamic hydrophone. 
































































































































































































’re 

:si 

SI 

■A 

NC 

;e 


























m\ 

> 

o 

TANCI 

L_ 
















FREQUENCY IN KC 


Figure 117. Impedance, electrodynamic hydro- 
phone. 



Figure 118. Electrodynamic hydrophone. 


DIAPHRAGM 



COIL 


MAGNET ASSEMBLE 


AIR DRYER 


Figure 119. Cross section, electrodynamic 
hydrophone. 




330 


INDUSTRIAL DESIGNS 


^ ^ RCA Magnetostriction Hydrophone 

Type: Magnetostriction (nickel). 

Designer and Manufacturer : Radio Corporation of America. 

References: USRL Orlando Project No. 117, March 4, 1944. 

See also, “Calibrated Subaqueous Microphones,” H. F. Olson 
and J. Preston, RCA Laboratories, October 26, 1943.2^’^ 
Use: As standard in calibration measurements. 

Description: The transducer element is a nickel tube % in. in diameter, 
2 in. in length, and 0.015 in. in wall thickness. The polarizing flux is sup- 
plied by four small Alnico magnets. A coil of insulated wire is wound 
around the magnets. 


<;^2cONllErafDEEr 


INDUSTRIAL DESIGN INSTRUMENTS 


331 



Figure 120. Receiving response, magneto- 
striction hydrophone. 


6000 









































































































































re; 

jISTA 

'JCE 

/ 





























J. 
















\f 

IE/ 

Ici 

'AN 

CE 












1 

1 









FREQUENCY IN KC 


Figure 121. Impedance, magnetostriction hydro- 
phone. 



Figure 122. Magnetostriction hydrophone. 



Figure 123. Cross section, magnetostriction 
hydrophone. 


332 


INDUSTRIAL DESIGNS 


USDAR 


Type: Quartz Crystal. 

Designer and Manufacturer: Radio Corporation of America. 

References: NDRC Report No. 6.1-sr 1130-1632, June 30, 1944.^1^ 
NDRC Report No. 6.1-srll30-1821, August 15, 1944.218 
NDRC Report No. 6.1-srll30-1822, August 18, 1944.21^ 

Use: Small object location by echo ranging. 

Description: The USDAR is a light, portable, hand-operated echo- 
ranging device which can be carried by one man and is used for locating 
small objects in the water, for example, in detecting mines during landing 
operations. It weighs about 5 lb and is cylindrical in shape and 10 in. long, 
as shown in Figure 132. A battery box weighing about 10 lb is connected 
to it by a 3-ft cable and must be carried with the unit. 

The device contains as an active element a 1-in. diameter circular quartz 
disk with a thickness resonance at 500 kc. One face of the crystal is in 
contact with the water. The associated electronic circuit shown in 
Figure 133 is supplied with power by the dry cells in the battery box. The 
principle of operation is as follows: A signal of midfrequency 500 kc is 
frequency modulated sinusoidally at a rate of 12 c with a frequency swing 
of ±4,000 c. This signal is continuously transmitted as sound by the crystal, 
and when the sound strikes an object, an echo is returned to the crystal. 
Thus both transmitted and received signal voltages appear across the 
crystal simultaneously. The associated circuit then selects the difference 
frequency of the transmitted and received signals. This is amplified by the 
audio frequency amplifier and impressed on two HA-1 type Western Elec- 
tric Company head receivers connected in series. 

There is a frequency difference between the echo and outgoing signal 
due to the transit time of the echo to and from the reflecting object. 
Figure 129A shows the frequencies of the echo and outgoing signal as 
functions of time, and Figure 129B shows the audio difference frequency 
as a function of time. Twice during each %2 of a second the signal and 
echo have the same frequency, so the audio difference frequency becomes 
zero at these instants. Between these instants the difference frequency 
reaches a maximum, the magnitude of which depends on the acoustic path 
length. The maximum audio frequency difference is given by (see 
Figure 130) 


2/rf sin (2(500)’ 

where fd = deviation frequency, 
fm = modulation frequency, 
d = object distance (feet). 

Thus the audio frequency increases with distance up to about 4,000 c 
at 100 ft and then decreases again. 

The magnitude of the audio signal is roughly proportional to the prod- 
uct of the outgoing signal and the echo magnitudes. Since the former is 
fixed, the audio frequency signal depends on the intensity of the echo, that 
is, on the type of reflecting object and on its distance. Thus the audio 
signal decreases with distance. This is shown in Figure 131, where the 

^CONFIDENTIAj^ 


PRESSURE AT I METER IN DB VS I DYNE /SO CM 
PER WATT AVAILABLE POWER FROM 72 OHMS 


INDUSTRIAL DESIGN INSTRUMENTS 


333 



Figure 124. Directivity patterns, USDAR 500 
at 495.6 kc. 



Figure 126. Receiving response, USDAR 500. 



400 450 500 550 600 

FREQUENCY IN KC 



Figure 125. Transmitting response, USDAR 
500. 


Figure 127. Impedance, USDAR 500. 


334 


INDUSTRIAL DESIGNS 


audio frequency voltage across the headphones is plotted against object 
distance. On this figure the decrease of signal level with decreasing dis- 
tance is due to overloading of the audio circuit. 

From the above description it is seen that the object distance can be 
approximately estimated from the frequency and intensity of the audio 
signal, as well as from its bearing (determined from direction in which 
the device is aimed) and approximate knowledge of the slope of the 
bottom. 

Experimental units operating at 250 kc and 1,000 kc were also tested. As 
shown in Table 1, the 1,000 unit was inferior to both the 250 and 500 units. 
The 250 unit performed as well as the 500, but ease in obtaining the smaller 
crystals used in the 500 led to the further development and improvement 
of the 500 unit. Modification in the gain characteristics of the audio fre- 
quency circuit resulted in the major part of the improvement of the 500 
modified over the 500-1 unit. 


Table 1. Calibration tests. 


Unit 

Diameter of 
crystal (in.) 

Self-driven 
pressure at 10 ft 
distance (db vs 

1 dyne per sq cm.) 

Receiving 
response at 
peak (db 
vs 1 volt) 

Audio response 
at 50 ft (db vs 

1 volt in series 
with crystal) 

Directivity 

index 

(db) 

Calculated signal 
reflector at 50 ft 
(db vs 1 volt) 

1000-2 

Yl 

81.4 

-94.5 

-3.9 

-27.5 

-52.2 

500-1 

1 

80.3 

-79.5 

-7.0 

-28.7 

-35.2 

250-1 

2 

81.6 

-76.2 

-0.45 

-28.2 

-38.0 

500 

modified 

1 

80.3 

-79.5 

-28.0 

-28.7 

-14.0 



Table 2. 

Performance tests. 


Unit 

Maximum 

range 

(ft) 

Noise 

voltage 

Audio frequency 
voltage across head 
receivers — reflec tor 
at 50 ft (db vs 1 volt) 

1000-2 

70 

0.02 

-51.0 

500-1 

120 

0.036 

-36.2 

250-1 

150 

0.035 

-33.8 

500 modified 

150 

0.1 

-25.0 


INDUSTRIAL DESIGN INSTRUMENTS 


335 



4905 4925 4945 4965 4985 5005 5025 

VARIABLE FREQUENCY IN KC 


Figure 128. Gain frequency characteristics of 
audio circuit of USDAR 500. 



Figure 130. Maximum frequency heard in 
phones versus distance to reflecting object. 



TIME IN SECONDS 

Figure 129. (A) Signal and echo frequencies 

as functions of time. (B) Audio difference fre- 
quency as a function of time. 



Figure 131. Volts across head receivers due to 
an echo as a function of distance to reflecting 
object. 



336 


INDUSTRIAL DESIGNS 



5600 IT4 .01 IT4 IS4 



CRYSTAL 



OPEN CIRCUIT VOLTS IN DB VS I VOLT 
FOR A SOUND FIELD OF I DYNE /SO CM 


INDUSTRIAL DESIGN INSTRUMENTS 


337 


General Electric Carbon Hydrophone 

Type: Carbon. 

Designer and Manufacturer : General Electric Company. 

Reference: NDRC Report No. C4-sr20-293, November 12, 1942.185 

Use: As sound element in a binaural listening system. 

Description: A carbon button is mounted inside a soft rubber cap. The 
button is closed by a plunger which is rigidly attached to a brass cylinder. 
The supply circuit consists of 41/2 v, dc, through a filter consisting of a 
series choke coil of 60 h inductance with 5.8 ohms d-c resistance and a 
i^-/xf shunt condenser. The response of the hydrophone is not a linear 
function of incident sound pressure as shown on the receiving response 
curve. 


-40 

-50 

-60 

-70 

-80 


Figure 134. Receiving response, carbon hydro- 
phone. 




-BRASS STRIP 


Figure 135. Carbon hydrophone. 




oNFiDKsniiir 


338 


INDUSTRIAL DESIGNS 


Underwater Object Locator 

Type: L-Cut Rochelle Salt Crystal. 

Designer and Manufacturer : General Electric Company. 

Reference: NDRC Report No. 6.1-srll30-2302, July 23, 1945.228 

Use: Small object location by echo ranging. 

Description and Application: The Underwater Object Locator [UOL] 
developed by the General Electric Company is a scanning sonar system 
that reproduces on a cathode-ray tube screen the shape of the reflecting 
object. In essence, this system floods a given area with sound and then 
proceeds to scan the reflections and presents them in their proper order 
on the screen. 

In practice, this system differs from the usual sonar systems in that the 
transmitter and receiver are each mounted in separate streamlined hous- 
ings. The transmitter is located on the starboard side of the vessel and 
the receiver on the port side. The transmitter radiates a sound beam 
about 10° wide and 18° high at a frequency of either 750 kc or 250 kc. 
This beam is swept from left to right to cover a field of view of 120° in 
about 2 sec and may be pointed anywhere between horizontal and 70° 
downward. The choice of frequency is determined by the range and defini- 
tion desired — 750 kc being used for greater definition and shorter effec- 
tive range. Either of these two frequencies may be chosen by simply 
rotating the combination of two projectors mounted back to back in the 
transmitter housing. One projector is designed for operation at 750 kc 
and the other at 250 kc. The active elements in both projectors are L-cut 
Rochelle salt crystals. Approximately 100 w of driving power is used with 
each projector. 

The receiver unit is a highly directional device selective to signals 
within a circular beam approximately 1° across. Thus the receiver looks 
at a spot only 20 in. in diameter at 100 ft. This narrow beam is obtained 
by use of a parabolic reflector 14 in. in diameter. 

Horizontal scanning is accomplished by mechanically rotating the 
receiver in synchronism with the transmitter; however, it is so arranged 
that the rotation of the receiver lags that of the transmitter in its sweep 
across the field of view. This lag allows time for the sound energy to travel 
out to the object and back again. The lag time or “range’’ is adjustable. 

Vertical scanning is accomplished by scanning electrically a vertical 
row of crystals in the receiving unit placed along the focal curve of the 
parabolic reflector. 

The receiving unit consists of two rows of small Rochelle salt crystals 
with 22 crystals in one row for operation at 750 kc and 16 crystals in the 
remaining row for operation at 250 kc. These crystals are X-cut Rochelle 
salt. Each of these crystals is connected to a capacity-type scanner which 
connects one crystal at a time to the following electrical system. This 
scanner rotates at a speed of about 3,600 rpm and is so constructed that 
it scans the elements three times in one revolution. This produces about 
4,000 picture elements in 1 sec for 750 kc operation. The vertical field of 
view is about 15° for both frequencies. 

Since in exploring small objects with highly directional beams any ex- 


fcONFIDENTIAlT^ 


PRESSURE AT I METER IN DB VS I DYNE /SO CM 
PER WATT AVAILABLE POWER FROM 72 OHMS 


INDUSTRIAL DESIGN INSTRUMENTS 


339 



Figure 136. Directivity pattern, projector 730 
No. 3 at 730 kc. Rotated around short axis. 


Figure 137. Directivity pattern, projector 730 
No. 3. Rotated around long axis. 




Figure 138. Transmitting response, projector Figure 139. Impedance, projector 730 No. 3. 

730 No. 3. 


reactance 



340 


INDUSTRIAL DESIGNS 


traneous motion can and will introduce distortion, the complete system 
has been stabilized for both pitch and roll. 

In some of the latest installations, three frequencies of transmission 
have been used in order to minimize cross talk. For the short (high defini- 
tion) range these are 710 kc, 730 kc, and 750 kc, while for the long range 
they are 210 kc, 230 kc, and 250 kc. For any given range the three fre- 
quencies are used successively in such a manner that the receiver is never 
tuned to the same frequency that is being transmitted at that instant. 
In addition to eliminating electric cross talk this technique also minimized 
extraneous acoustic signals due to reflection from close objects, such as 
the hull of the ship. The switching time is adjustable and may be tied in 
with the range control. 

The range of this instrument is, of course, a function of the size and 
shape of the reflecting object. For large objects, e.g., a submarine, the 
maximum range at which fair definition is preserved is on the order of 
600 ft. For smaller objects, such as mine cases, the maximum range is 
on the order of 130 ft. 

Directivity index of projector 730 No. 3: At 730 kc = —25.5 db. 




GLOSSARY 


Acoustic Axis. Reference line adopted in transducer 
calibration, usually the direction of maximum re- 
sponse. 

ADP. Ammonium dihydrogen phosphate crystal having 
marked piezoelectric properties. 

Asdic. British echo-ranging equipment; letters are de- 
rived from “Anti-Submarine Development Investiga- 
tion Committee.” 

Baffle. A shield used to modify an acoustic path. 

BDI. Bearing deviation indicator. 

BTL. Bell Telephone Laboratories. 

Cavitation. The formation of vapor or gas cavities in 
water, caused by sharp reductions in local pressure. 

Chemical Recorder. An indicator which records range 
on chemically treated paper. 

Crest Factor. In this volume, V 2 times the ratio of the 
peak-to-rms pressure of an acoustic wave. 

Crystal Transducer. A transducer which utilizes 
piezoelectric crystals, usually Rochelle salt, ADP, 
quartz, or tourmaline. 

CUDWR. Columbia University Division of War Re- 
search. 

CUT-ONS. Method of bearing determination from initial 
and final echoes obtained as the echo-ranging beam 
is swept across the target. 

DDL Depth deviation indicator. 

Directivity Index. A measure of the directional 
properties of a transducer. It is the ratio, in db, of 
the average intensity, or response, over the whole 
sphere surrounding the projector, or hydrophone, to 
the intensity, or response, on the acoustic axis. 

Dome. A transducer enclosure, usually streamlined, 
used with echo-ranging or listening devices to 
minimize turbulence and cavitation noises arising 
from the passage of the transducer through the 
water. 

DTMB. David Taylor Model Basin. 

Echo Repeater. Artificial target, used in sonar calibra- 
tion and training, which returns a synthetic echo by 
receiving, amplifying, and retransmitting an incident 
ping. 

ERSB. Expendable radio sono buoy. 

Hydrophone. An underwater microphone. 

Hydrophone, Velocity-Type. A pressure-gradient 
hydrophone. 

JP, JT. Submarine sonic listening systems employing 
magnetostriction hydrophones. 

Magnetostriction Effect. Phenomenon exhibited by 
certain metals, particularly nickel and its alloys, 
which change in length when magnetized, or (Villari 
effect) when magnetized and then mechanically dis- 
torted, undergo a corresponding change in magnetiza- 
tion. 

MIT-USL. Massachusetts Institute of Technology 
Underwater Sound Laboratory. 

NDRC. National Defense Research Committee. 

NLL. New London Laboratory of CUDWR. 

NOL. Naval Ordnance Laboratory. 

NRL. Naval Research Laboratory. 

N-Series (transducers). Navy designation for echo- 
sounding equipment. 

OSRD. Office of Scientific Research and Development. 

Piezoelectric Effect. Phenomenon, exhibited by cer- 
tain crystals, in which mechanical compression 
produces a potential difference between opposite 


crystal faces, or an applied electric field produces 
corresponding changes ini dimensions. 

Ping. Acoustic pulse signal projected by echo-ranging 
transducer. 

PPL Plan position indicator. 

Pressure-Gradient Transducer. Transducer, such as 
a moving-ribbon hydrophone, in which the moving 
element responds to pressure difference rather than 
to pressure. 

Projector. An underwater acoustic transmitter. 

QC. Standard Navy echo-ranging equipment using a 
magnetostriction transducer. 

QH. Navy designation for CR scanning sonar (originally 
applied to HUSL designs) using magnetostriction 
transducers. 

QL. Navy designation for FM sonar of UCDWR de- 
sign. 

Radio Sono Buoy. A buoy listening device that con- 
tains a hydrophone for receiving target signals and 
a radio transmitter for relaying the signals to 
patrolling air or surface craft. 

Rear Response. The maximum pressure within ±60 
degrees from the rear of the transducer in db rela- 
tive to the pressure on the acoustic axis. 

Recognition Differential. The number of db by 
which a signal must exceed the background in order 
to be recognized 50 per cent of the time. 

pc-RuBBER. A rubber compound with the same pc 
(density X velocity of sound) product as water. 

Rochelle Salt. Potassium sodium tartrate 
(KNaC4H406*4H20) piezoelectric crystal used in 
sonar transducers. 

Scanning Sonar. Echo-ranging system in which the 
ping is transmitted simultaneously throughout the 
entire angle to be searched, and a rapidly rotating 
narrow beam scans for the returning echoes. 

Searchlight-Type Sonar. Echo-ranging system in 
which the same narrow beam pattern is used for 
transmission and reception. 

Sonar. Generic term applied to methods or apparatus 
that use sound for navigation and ranging. 

Sonic Frequencies. Range of audible frequencies, 
sometimes taken as from 0.02 kc to 15 kc. 

SPTU. Split projector test unit. 

Supersonic Frequencies. Range of frequencies higher 
than sonic. Sometimes referred to as ultrasonic to 
avoid confusion with growing use of the term super- 
sonic to denote higher-than-sound velocities. 

Target Strength. Measure of reflecting power of 
target. Ratio, in db, of the target echo to the echo 
from a 6-ft diameter perfectly reflecting sphere at 
the same range and depth. 

Transducer. Any device for converting energy from 
one form to another (electrical, mechanical, or 
acoustical). In sonar, usually combines the functions 
of a hydrophone and a projector. 

UCDWR. University of California Division of War 
Research. 

USRL. Underwater Sound Reference Laboratories. 

X-CUT. A cut in which the electrode faces of a piezo- 
electric crystal are perpendicular to an X or elec- 
trical axis. 

Y-Cut. a cut in which the electrode faces of a piezo- 
electric crystal are perpendicular to a Y or mechan- 
ical axis. 



BIBLIOGRAPHY* 


Numbers such as Div. 6-551-Ml indicate that the document listed has been microfilmed and that its 
title appears in the microfilm index printed in a separate volume. For access to the index volume and to the 
microfilm, consult the Army or Navy agency listed on the reverse of the half-title page. 


CHAPTER 1 

1. A Survey of Ship Sounds. Measurements and 
Analyses Made from April 1-August 6, 191^1, 
MIT Research Project DIG 5985, MIT-USL. 

Div. 6-551-Ml 

2. Preliminary Calibrations of Brush Crystal Hydro- 
phone, Model Cll-Al, Serial No. 6, Eginhard 
Dietze, NDRC 176, Report 2420, BTL, Dec. 24, 

1941. ' Div. 6-554.3-M2 

3. A Primary Standard Pressure Gy'adient Hydro- 
phone, NDRC C4-sr212-058, BTL, Mar. 2, 1942. 

Div. 6-553.1-Ml 

4. Underwater Measurement Microphones — Infor- 
mation Relating to Calibration Curves, Operating 
Instructions, Plans, Techniques, LR-47, Brush 
Development Co., Mar. 4, 1942. 

5. Performance Characteristics and Operating In- 
structions for IJ Type Projector, BTL, Apr. 28, 

1942. Div. 6-553.2-Ml 

6. A Subaqueous Projector for Hydrophone Calibra- 

tions in the Audible Frequency Range, Reginald 
L. Jones, OSRD 705, NDRC C4-sr212-103, BTL, 
June 1, 1942. Div. 6-553.2-M3 

7. Calibration of Crystal Hydrophones Cll-Al #16, 

Cll-Al #17, and HK-15, Norma Bailey and 
Eginhard Dietze, NDRC C4-sr20-147, USRL, July 
27, 1942. Div. 6-554.3-MlO 

8. Calibration of Crystal Hydrophones ClO-Al #11, 
and Cll-Al #13, Norma Bailey and Eginhard 
Dietze, NDRC C4-sr20-148, USRL, July 27, 1942. 

Div. 6-554.3-M9 

9. Underwater Sound Standard Hydrophones, Pro- 
jectors, and Calibration Apparatus Developed by 
Bell Telephone Laboratories for the NDRC, Rob- 
ert S. Shankland, USRL, Aug. 1, 1942. 

Div. 6-553-M2 

10. Operating Notes, Standard Crystal Hydrophone 
No. ESO 572081, BTL, Aug. 29, 1942. 

11. The HK Microphone Preamplifier, A. A. Pe- 

trauskas, MIT Research Project DIC 5985, Series 
A4 No. 5 and No. 7, MIT-USL, Sept. 2 and Sept. 
14, 1942. Div. 6-554.3-Mll 

*BTL Bell Telephone Laboratories, Inc. 

CUDWR-NLL Columbia University Division of War Research at 
the U. S. Navy Underwater Sound Laboratory. 

HUSL Harvard Underwater Sound Laboratory. 

MIT-USL Massachusetts Institute of Technology Underwater 
Sound Laboratory. 

NRL Naval Research Laboratory. 

RCA Laboratories Radio Corporation of America. 

UCDWR University of California Division of War Research at 
the U. S. Navy Radio and Sound Laboratory. 

USRL Underwater Sound Reference Laboratories of Columbia 
University Division of War Research. 


12. Free Field Reciprocity Calibrations of Under- 

water Sound Reference Laboratories^ Standards, 
Leslie L. Foldy, NDRC C4-sr20-206, USRL, Sept. 
11, 1942. Div. 6-552-M3 

13. Calibration Measurements of the Crystal Hydro- 

phone Cll-Al #11 with Special NOL Preampli- 
fier, Eginhard Dietze, NDRC C4-sr20-282, USRL, 
Sept. 15, 1942. Div. 6-554.3-M12 

14. A Standard Crystal Hydrophone, NDRC C4- 
sr212-507, BTL, Oct. 1, 1942. Div. 6-553.1-M2 

15. Standard Supersonic Projectors, NDRC 6.1-sr212- 

625, BTL, Jan. 21, 1943. Div. 6-553.2-M5 

16. Calibration Measurements on Crystal Projectors 
2B #7 and SB #8, Eginhard ^Dietze, NDRC 
6.1-sr20-602, USRL, Jan. 27, 1943. 

Div. 6-554.1-M3 

17. Information on Low Frequency Secondary Stand- 

ard Hydrophones HKC-126 and HKC-127, MIT 
Research Project DIC 5985, Series Al, No. 10, 
MIT-USL, Mar. 5, 1943. Div. 6-554-M18 

18. Condenser Hydrophone for Frequencies Below 

75 Cycles Per Second, Earle C. Gregg, Jr., MIT 
Research Project DIC 5985, Series Al, No. 12, 
MIT-USL, Apr. 1, 1943. Div. 6-553.1-M4 

19. Preliminary Calibration of Three MIT Crystal 

Hydrophones HKB-65, HKB-121 , and HKB-125, 
One MIT Magnetostriction Hydrophone HU-9, 
and the British Low Frequency Quartz Crystal 
Hydrophone, Norma Bailey, NDRC 6.1-sr20-619, 
USRL, May 6, 1943. Div. 6-554.3-M21 

20. Handbook of D.I.C. Hydrophones, J. E. White 
and R. M. Gogolick, MIT Research Project DIC 
5985, Series Al, No. 13, MIT-USL, May 17, 1943. 

Div. 6-554-M22 

21. Low Frequency Calibration of Three MIT Crystal 
Hydrophones HKB-65, HKB-121, and HKB-125, 
One MIT Magnetostriction Hydrophone HU-9 
and the British Low Frequency Quartz Crystal 
Hydrophone 2VLF, Leslie L. Foldy, NDRC 6.1- 
sr20-879, USRL, June 19, 1943. Div. 6-554-M25 

22. Calibration of the Naval Research Laboratory 

Tourmaline Hydrophones OL-A-3 and OL-A-Ip, 
D. Bernard Simmons, NDRC 6.1-sr20-884, USRL, 
June 28, 1943. Div. 6-554.3-M23 

23. Low Frequency Calibration Measurements on 

MIT Crystal Hydrophones XMS-5, HKC-126, and 
HKC-127, and MIT Condenser Hydrophone 
CMF-3, Leslie L. Foldy, NDRC 6.1-sr20-881, 
USRL, June 30, 1943. Div. 6-553.1-M5 

24. A Practical Dictionary of Underwater Acoustical 

Devices, NDRC 6.1-sr20-889, OSRD 772, USRL, 
July 27, 1943. Div. 6-554-M28 

25. Condensed Description of Brush Hydrophones and 


344 


BIBLIOGRAPHY 


26. 

27. 

28. 

29. 


30. 


31. 

32. 

33. 

34. 

35. 

36. 

37. 

38. 

39. 


40. 


41. 


42. 


Underwater Transducers, LR-118, Brush Devel- 43. 
opment Co., Sept. 9, 1943. 

Measurements of 3 A, No. 35 Crystal Hydrophone, 
Edward Gerjuoy, Report G12/579, CUDWR-NLL, 

Oct. 30, 1943. Div. 6-554.3-M30 44. 

A Wide Range Projector for the Lower Audible 
and Upper Subsonic Frequencies, NDRC 6.1- 
sr783-1213, BTL, Nov. 20, 1943. Div. 6-553.2-M6 45. 

Performance Characteristics and Operating In- 
sty'uctions for NDRC 4A Projector, BTL, Dec. 6, 

1943. Div. 6-553.2-M7 

Calibration of Two B19B Magnetostriction Hy- 46. 
drophones Nos. 61 and 67, Frank H. Graham, 

NDRC 6.1-srll30-1199, USRL, Jan. 17, 1944. 

Div. 6-554.2-M16 

Calibration of HKC-59, HKB-78, XMX-1, and 47. 
B19B #25 Hydrophones, L. Pauline Leighton, 

NDRC 6.1-srll30-1362, USRL, Feb. 1, 1944. 

Div. 6-554.3-M36 

Wide Range Hydrophone for Low Sound Fields, 48. 
NDRC 6.1-sr346-1321, BTL, Mar. 20, 1944. 

Div. 6-553.1-M7 

Calibration of 5D-1 Crystal Hydrophone, D. Ber- 
nard Simmons, NDRC 6.1-srll30-1375, USRL, 49. 

Apr. 13, 1944. Div. 6-554.3-M38 

Operating Notes for 6B Crystal Projector, BTL, 

May 30, 1944. Div. 6-554.1-M5 

Calibration Tests on Four XMX Hydrophones, 50. 
L. Pauline Leighton, NDRC 6.1-srll30-1635, 

USRL, July 11, 1944. Div. 6-554.3-M41 

Wide Range Supersonic Projector for Calibration 51. 
Work, NDRC 6.1-sr783-1325, BTL, Aug. 10, 1944. 

Div. 6-553.2-M9 

Calibration System in the Loiver Megacycle 
Range, NDRC 6.1-sr783-1697, BTL, Aug. 17, 1944. 52. 

Div. 6-552-M12 

Transducer Calibration Techniques, Status Re- 
port, HUSL, Dec. 1, 1944. Div. 6-552-M15 

Calibration Projector for Frequencies from 20 to 53. 
150 Kilocycles, W. H. Martin, NDRC 6.1-sr783- 
1329, BTL, Feb. 7, 1945. Div. 6-553.2-MlO 

Standards Used by the USRL, NDRC 6.1-srll30- 
2303, USRL, July 23, 1945. Div. 6-552-M20 54. 


CHAPTER 2 

Analysis of Calibration Data of Magnetostriction 55. 
Echo Ranging Equipment, Walter D. Goodale, 

Jr., and Eginhard Dietze, BTL, Mar. 18, 1942. 

Div. 6-554-MlO 

Preliminary Calibration of Magnetostriction 56. 
Echo Ranging (QC) Projectors and Crystal (JK) 
Supersonic Listening Unit, Walter D. Goodale, 

Jr., and Eginhard Dietze, BTL, Mar. 18, 1942. 

Div. 6-556.1-Ml 

Analysis of Measurements of Crystal (JK) Echo 57. 
Ranging Projector, Walter D. Goodale, Jr., and 
Eginhard Dietze, BTL, Mar. 27, 1942. 

Div. 6-554.1-Ml 


% 



DENXI 


Calibration Measurements on Crystal Supersonic 
Listening Unit JK-9, Frank H. Graham and 
Eginhard Dietze, NDRC C4-sr20-115, USRL, 
June 20, 1942. Div. 6-556.1-M2 

Calibration of Submarine Signal Company Echo- 
Ranging Projector, Eginhard Dietze, NDRC C4- 
sr20-202, USRL, Sept. 3, 1942. Div. 6-556.1-M3 
Calibration Measurements on Parabolic Hydro- 
phone Assembly Navy Type CBD-51035, Thomas 
Blewitt, NDRC C4-sr20-280, USRL, Sept. 23, 

1942. Div. 6-556.1-M4 

Calibration of Subniarnne Signal Company 
WEA-2 Combination Projector and Dome, Norma 
Bailey, Eginhard Dietze, NDRC C4-sr20-295, 
USRL, Nov. 16, 1942. Div. 6-556.1-M5 

Note on Back and Side Radiation of the WEA-1 
(RCA 9-inch) Projector, Robert L. Cummerow 
and Francis P. Bundy, NDRC C4-sr287-380, 
HUSL, Nov. 21, 1942. Div. 6-556.1-M6 

Measurement of the Angular Characteristics of 
the WEA-1 Projector, Edward Gerjuoy, Report 
G13/175, CUDWR-NLL, Feb. 23, 1^3. 

Div. 6-556.1-M7 

RCA Echo-Ranging Equipment WEA-1 Serial 
No. 159, and RCA Engineering Standard WEA-1 
Projector, Eginhard Dietze, NDRC 6.1-sr20-607, 
USRL, Feb. 25, 1943. Div. 6-556.1-M8 

Angular Characteristics of the WEA-1 Used as 
a Hydrophone, Edward Gerjuoy, Report G13/176, 
CUDWR-NLL, Mar. 2, 1943. Div. 6-556.1-M9 

Calibration of U. S. Navy Sound Power Units 
355^-L-D (Serial Number), Frank H. Graham, 
NDRC 6.1-sr20-611, USRL, Mar. 10, 1943. 

Div. 6-556.1-MlO 
Calibration Measurements on Several WEA-1 
RCA Echo-Ranging Projectors, Eginhard Dietze, 
NDRC 6.1-sr20-875, USRL, June 4, 1943. 

Div. 6-556.1-Mll 

Calibration of QBG Crystal Transducer No. 603, 
L. Pauline Leighton, Eginhard Dietze, NDRC 
6.1-sr20-941, USRL, July 21, 1943. 

Div. 6-556.1-M13 

Overall Calibration of NL 105 #9 Amplifier and 
COG51053 #30 Hydrophone and Baffle, Roland G. 
Quest, Report G12/G7/447, CUDWR-NLL, July 
21, 1943. Div. 6-556.1-M12 

Calibration of JP Nos. 1, 2, 3, and U, and COG 
51053 Tubular Magnetostriction Hydrophones, 
D. Bernard Simmons, NDRC 6.1-sr20-942, USRL, 
July 22, 1943. Div. 6-556.1-M14 

Calibration of Two Experimental Model Mag- 
netostriction Projectors, QGB-A and QGB-B, for 
use in BDI Modified Echo Ranging, Frank H. 
Graham, NDRC 6.1-sr20-943, USRL, July 23, 

1943. Div. 6-556. 1-M15 

Calibration of an Experimental Model Magneto- 
striction 26 KC Projector QGB Model C, Frank 
H. Graham, NDRC 6.1-srll30-957, USRL, Sept. 
28, 1943. Div. 6-556. 1-M16 


BIBLIOGRAPHY 


345 


58. Calibration of a Ilk" ADP Ci'ystal Projector 

AX63 #1, Manufactured by the Brush Develop- 
ment Company, Leslie L. Foldy, Frank H. 
Graham, NDRC 6.1-srll30-1187, USRL, Nov. 16, 
1943. Div. 6-556.1-M17 

59. Measurements of C-35 Brush Crystal Hydro- 
phone (Navy JO Gear), Edward Gerjuoy, Report 
G12/619, CUDWR-NLL, Nov. 20, 1943. 

Div. 6-554.3-M35 

60. Calibration of Hydrophones Used ivith the Model 

JQ and Modified JQ Sound Receiving Equipments, 
Frank H. Graham, NDRC 6.1-srll30-1190, USRL, 
Dec. 14, 1943. Div. 6-556.1-M18 

61. Calibration of Submarine Signal Company Ex- 
perimental ADP Crystal Projector SK 5982 in 
QB Housing, Eginhard Dietze, NDRC 6.1-srll30- 
1191, USRL, Dec. 15, 1943. Div. 6-556.1-M19 

62. Measurements on QB Transducer CBM 78115 

#41, C. J. Burbank, Report C32, UCDWR, Dec. 
17, 1943. Div. 6-556.1-M20 

63. Calibration of QC Projector CBM 78183 #565, 
Frank H. Graham, Eginhard Dietze, NDRC 6.1- 
srll30-1196, USRL, Jan. 4, 1944. Div. 6-556.1-M21 

64. Calibration of a (QB) 733 J Transducer, David 

W. Van Lennep, Report G27/718, CUDWR-NLL, 
Apr. 28, 1944. Div. 6-556.1-M22 

65. Calibration of Four (QB) 733R Transducers, 

David W. Van Lennep, Report G27/878, CUDWR- 
NLL, May 1, 1944. Div. 6-556.1-M23 

66. Sonar Bulletin, Bureau of Ships, Navy Depart- 
ment, NavShips 900,025.4, June 1, 1944. 

67. Calibration of 94111A, 94120 and 94211A Trans- 
ducers and the 100" Dome Used in the QGA Echo- 
Ranging System, Frank H. Graham, NDRC 6.1- 
srll30-1626, USRL, June 7, 1944. 

Div. 6-556.1-M24 

68. Calibration of QBE Projector #461 in Dome #14, 

Eginhard Dietze, NDRC 6.1-srll30-1634, USRL, 
July 5, 1944. Div. 6-556.1-M25 

69. Measurements on QB Submarine Signal Company 
Projector, Eginhard Dietze, NDRC 6.1-srll30- 
1820, USRL, Aug. 11, 1944. Div. 6-556.1-M26 

70. Calibration of Harvard Underwater Sound Lab- 
oratory HP4 #1 Laminated Stack Transducer, 
Sword Arm Depth Angle Transducer, and B19H 
Hydrophone, Eginhard Dietze, NDRC 6.1-srll30- 
1826, USRL, Aug. 28, 1944. Div. 6-556.1-M27 

71. Calibration of Submarine Signal Company Pro- 
jector 947 #65 (U. S. Navy CBM 78214) for 
Fathometer Use, Frank H. Graham, NDRC 6.1- 
srll30-1837, USRL, Oct. 13, 1944. 

Div. 6-556.1-M28 

72. Calibration of ADP, QGB and NMC Sonar-Rang- 
ing Projectors Manufactured by the Radio Cor- 
poration of America, Frank H. Graham, NDRC 

6.1-srll30-1985, USRL, Jan. 16, 1945. 

Div. 6-556.1-M30 

73. Calibration of QJB Projector #637, Eginhard 
Dietze and Genevieve D. Weldon, NDRC 6.1- 


srll30-1986, USRL, Jan. 16, 1945. 

Div. 6-556.1-M29 

74. Calibration of Two ADP Crystal Projectors, 
Eginhard Dietze and Genevieve D. Weldon, 
NDRC 6.1-srll30-1988, USRL, Jan. 25, 1945. 

Div. 6-556.1-M31 

75. Calibration of the Naval Research Laboratory 

Tourmaline Hydrophones OL-A-1 and OL-A-2, 
Cathleen Anderson, NDRC 6.1-srll30-2132, 
USRL, Jan. 31, 1945. Div. 6-556.1-M32 

76. Calibration of BTL ADP Crystal Projector, 
Eginhard Dietze and L. Pauline Leighton, NDRC 

6.1- srll30-2131, USRL, Feb. 1, 1945. 

Div. 6-556.1-M33 

77. Calibration of Experimental QCU Projector 
Models #1 and #2, Eginhard Dietze, NDRC 

6.1- srll30-2138, USRL, Feb. 24, 1945. 

Div. 6-556.1-M34 

78. Captured Japanese Acoustic Equipment, Egin- 

hard Dietze, NDRC 6.1-srll30-2291, USRL, May 
24, 1945. Div. 6-556.1-M35 

79. Experimental ^'Football Type” WFA-1 Topside 
Projector, Frank H. Graham, NDRC 6.1-srll30- 
2295, USRL, June 25, 1945. Div. 6-556.1-M36 

80. U. S. Navy Sonar Equipments, NDRC 6.1-srll30- 

2307, Aug. 24, 1945. Div. 6-556.1-M37 

CHAPTER 3 

81. Memorandum regarding Recent Tests on Domes 

under NRL Supervision, G. P. Harnwell, Division 
6 Selection and Training Committee, Aug. 12, 

1941. Div. 6-555-Ml 

82. Calibration of Steel Domes for Echo-Ranging 

Projectoi's, Eginhard Dietze, NDRC C4-sr20-153, 
USRL, Aug. 7, 1942. Div. 6-555-M3 

83. Directivity Measurements on British Type Steel 

Dome for Echo-Ranging Projectors, Norma 
Bailey and Eginhard Dietze, NDRC C4-sr20-289, 
USRL, Oct. 26, 1942. Div. 6-555-M4 

84. Echo-Ranging Performance of Budd 1/16" Cor- 
rugated Domes filled with Prestone and Water, 
R. B. Bowersox, C. M. Clay, and others, NDRC 

6.1- sr287-769, HUSL, Apr. 30, 1943. 

Div. 6-555-M5 

85. Advantages of Aluminum as a Dome Material — 
Theoretical Study, Leslie L. Foldy, NDRC 6.1- 
sr20-882, USRL, June 23, 1943. Div. 6-555-M6 

86. Calibration Tests on Two 54-Inch British Type 

Domes with Expanded Metal Stainless Steel Win- 
dows, Eginhard Dietze, NDRC 6.1-sr20-887, 
USRL, July 6, 1943. Div. 6-555-M7 

87. Calibration Tests on a 57" Budd Dome with Ex- 
panded Metal Stainless Steel Window, Genevieve 
D. Weldon and Eginhard Dietze, NDRC 6.1- 
sr20-948, USRL, Aug. 16, 1943. Div. 6-555-M9 

88. Calibration Measurements on an RCA 9" Projec- 
tor with 1/16" Corprene Band in a .020" Experi- 
mental WEA-1 Dome, Eginhard Dietze, NDRC 


346 


BIBLIOGRAPHY 


6.1- sr20-951, USRL, Aug. 24, 1943. 

Div. 6-555-MlO 

89. Calibration Tests on a 100" Expanded Metal 

Stainless Steel Dome Section (QGA), L. Pauline 
Leighton and Eginhard Dietze, NDRC 6.1-sr20- 
953, USRL, Sept. 2, 1943. Div. 6-555-Mll 

90. Calibration Measurements on a Modified WEA-1 

Dome — New London B Dome, L. Pauline Leigh- 
ton and Frank H. Graham, NDRC 6.1-sr20-954, 
USRL, Sept. 2, 1943. Div. 6-555-M12 

91. Calibration of Model C Dome for WEA-1 Echo- 
Ranging System, L. Pauline Leighton, NDRC 

6.1- srll30-959, USRL, Oct. 15, 1943. 

Div. 6-555-M13 

92. Calibration Measurements on an Aluminum Dome 
and Two Steel Domes for Use with WEA-1 Equip- 
ment, L. Pauline Leighton, NDRC 6.1-srll30- 
1192, USRL, Dec. 15, 1943. Div. 6-555-M14 

93. Calibration Tests on the NRL Corrugated Dome, 

L. Pauline Leighton, NDRC 6.1-srll30-1194, 
USRL, Dec. 28, 1943. Div. 6-555-M15 

94. The Acoustic Properties of Domes — Part I, Henry 

Primakoff, NDRC 6.1-srll30-1197, USRL, Jan. 5, 
1944. Div. 6-555-M16 

95. The Acoustic Properties of Domes — Part II, 

Henry Primakoff, NDRC 6.1-srll30-1366, USRL, 
Feb. 18, 1944. Div. 6-555-M17 

96. The Effect of NRL Anti-Fouling Paint #36^ on 
the Acoustic Properties of a 54-Inch Dome, 
L. Pauline Leighton and Eginhard Dietze, NDRC 

6.1- srll30-1368, USRL, Mar. 6, 1944. 

Div. 6-555-M18 

97. Calibration of 54-Inch Expanded Metal Stainless 

Steel Budd Dome with Reinforcements, Eginhard 
Dietze, NDRC 6.1-srll30-1373, USRL, Apr. 5, 
1944. Div. 6-555-M19 

98. Calibration of the QCU #3 and QCU #5 Pro- 
jectors in the QCU Dome, Frank H. Graham, 
NDRC 6.1-srll30-1379, USRL, Apr. 28, 1944. 

Div. 6-555-M20 

99. Comparison of Two 54" Domes, one Equipped 

with 20-mil Window and the other with 30-mil 
Window, Eginhard Dietze, NDRC 6.1-srll30- 
1628, USRL, June 19, 1944. Div. 6-555-M21 

100. Effect of NRL Anti-Fouling Paint #364 Used 

on Domes, Report C57, Calibration Group, 
UCDWR, June 22, 1944. Div. 6-555-M22 

101. Monitoring CBM-78165A Projectors Inside 54- 

Inch Domes, Report C58, Calibration Group, 
UCDWR, June 23, 1944. Div. 6-555-M23 

102. The Effect of NRL Anti-Fouling Paint #364 on 
the Acoustic Properties of Echo-Ranging Domes, 
Eginhard Dietze and Frank H. Graham, NDRC 

6.1- srll30-1633, USRL, July 1, 1944. 

Div. 6-555-M24 

103. Calibration of 54" Dome with Experimental NRL 
Rubber Window, Eginhard Dietze, NDRC 6.1- 
srll30-1982, USRL, Jan. 3, 1945. 


104. Vertical Directivity Tests on NRL Corrugated 
Dome, Eginhard Dietze and Genevieve D. Weldon, 
NDRC 6.1-srll30-2143, USRL, Feb. 28, 1945. 

Div. 6-555-M28 

CHAPTER 4 

105. Calibration of British Echo-Ranging Unit Asdic 

A/S 96, Edwin Carstensen, NDRC 6.1-sr20-608, 
USRL, Mar. 4, 1943. Div. 6-556.2-Ml 

106. Calibration of British Quartz Crystal Hydro- 

phone #34, Eginhard Dietze, NDRC 6.1-srll30- 
1364, USRL, Feb. 4, 1944. Div. 6-556.2-M2 

107. Measurements on Type 135 Asdic Magnetostric- 

tion Transducer, Report 53, UCDWR, May 18, 
1944. Div. 6-556. 2-M3 

108. Calibration of British Quartz Crystal Hydro- 

phone #34, Addendum to Report 6.1-srll30-1364, 
Eginhard Dietze, NDRC 6.1-srll30-1623, USRL, 
May 24, 1944. Div. 6-556.2-M4 

109. Calibration of Asdic Set, Type 135, Erwin F. 

Shrader, NDRC 6.1-srll30-1827, USRL, Sept. 4, 
1944. Div. 6-556. 2-M5 

110. Calibration of Asdic Transducer, Type 150. 

Erwin F. Shrader, NDRC 6.1-srll30-2136, USRL, 
Feb. 17, 1945. Div. 6-556.2-M7 

CHAPTER 5 

111. Preliminary Calibration of Two Pressure Gradi- 

ent Type Hydrophones coded T-22, furnished by 
the Signal Corps Laboratory, Fort Monmouth, 
New Jersey, Frank H. Graham, Report 2420, 
BTL, Feb. 6, 1942. Div. 6-554-M8 

112. Calibration Measurements on Naval Ordnance 

Laboratory's Standard Velocity Type Hydrophone 
SV-1, Norma Bailey, NDRC C4-sr20-lll, USRL, 

June 18, 1942. Div. 6-554-M12 

113. Calibration Measurements of Hydrophones Used 

in the GR-5 and GR-7 Offshore Units for Harbor 
Defense, Frank H. Graham, NDRC C4-sr20-294, 
USRL, Nov. 13, 1942. Div. 6-554-M15 

114. Calibration of C21-A2 #1 and C21-A2 #5 Hydro- 

phones from the David Taylor Model Basin, 
Frank H. Graham, NDRC 6.1-sr20-877, USRL, 
June 14, 1943. Div. 6-554-M24 

115. Calibration of Naval Ordnance Laboratory Hy- 

drophones Mark I and Mark II and Naval Ord- 
nance Laboratory Standard Hydrophone SV #2, 
Eginhard Dietze, NDRC 6.1-sr20-886, USRL, 
June 30, 1943. Div. 6-553.1-M6 

Calibration of C21-A2 #1 and C21-A2 #5 Hydro- 
phones from the David Taylor Model Basin, 
Frank H. Graham, NDRC 6.1-sr20-947, USRL, 
Aug. 11, 1943. Div. 6-554-M29 

Recommended Calibration of Block Island Cable 
System, Henry B. Hoff, Report D12A/1118, 
CUDWR-NLL, Sept. 7, 1944. Div. 6-554-M35 

Calibration of NRL Small Object Locator, Egin- 

hard Dietze, NDRC 6.1-srll30-1979, USRL, Dec. 

Div. 6-554.4-Mll 



116. 

117. 

118. 


BIBLIOGRAPHY 


347 


119. Calibration of NRL X7 Transducer, Eginhard 

Dietze, NDRC 6.1-srll30-2309, USRL, Aug. 29, 
1945. Div. 6-554-M38 

CHAPTER 6 

120. Preliminary Calibration of Crystal Hydrophones 
Designed for Harbor Defenses, Frank H. Graham, 
Report 2420, BTL, Jan. 2, 1942. Div. 6-554.3-M3 

121 . Preliminary Calibration of Two Hydrophones 

Designed by Mr. A. L. Thuras — Inertia Type 
Hydrophone (TIH #4), and Magnetostriction 
Type (TMSH #1), Frank H. Graham, Report 
2420, BTL, Jan. 9, 1942. Div. 6-554-M7 

122. The Tubular Magnetostriction Microphone, Ar- 
thur L. Thuras, NDRC C4-sr20-095, Report 
G4/1937, ‘CUDWR-NLL, Mar. 17, 1942. 

Div. 6-554.2-Ml 

123. Preliminary Calibration of Thuras Type Magneto- 
striction Hydrophones for Harbor Defenses, Re- 
port 2420, BTL, Apr. 29, 1942. 

Div. 6-554.2-M2 

124. Calibration of Crystal Hydrophones HK18 and 

HK35 and of Portable Acoustic Range Sound 
Level Indicatoi'S Par 5 and Par 6, Eginhard 
Dietze and William F. Offutt, NDRC C4-sr20-113, 
USRL, June 15, 1942. Div. 6-554.3-M5 

125. Development of the Directional Voice — Frequency 
Toroidal Magnetostriction Hydrophone, Arthur 
L. Thuras, OSRD 775, NDRC C4-sr20-214, Re- 
port G55/3413, CUDWR-NLL, July 1, 1942. 

Div. 6-554.2-M3 

126. Calibration of MIT Crystal Hydrophones HK-29, 

HP-3 and HP-5, and British Crystal Hydrophone 
Standard No. 2U, Frank H. Graham and William 
F. Offutt, NDRC C4-sr20-132, USRL, July 15, 
1942. Div. 6-554.3-M8 

127. Calibration of Toroidal Magnetostriction Hydro 

phone with Backing Plate to Reduce Rear Re- 
sponse, William F. Offutt, NDRC C4-sr20-155, 
USRL, Aug. 3, 1942. Div. 6-554.2-M4 

128. Calibration of Two 4-Ft. Thuras Magnetostric- 

tion Hydrophones No. 9 and No. 10, Norma Bailey 
and Eginhard Dietze, NDRC C4-sr20-203, USRL, 
Sept. 1, 1942. Div. 6-554.2-M8 

129. Calibration Tests on Toroidal Magnetostriction 
Hydrophone System, Norma Bailey and Eginhard 
Dietze, NDRC C4-sr20-284, USRL, Sept. 25, 1942. 

Div. 6-554.2-MlO 

130. Calibration of Two C-23 Hydrophones (Serial 
Nos. 703 and 707) and one HK-21 Hydrophone 
(MIT Die 5985), Frank H. Graham, NDRC C4- 
sr20-298, USRL, Nov. 20, 1942. 

Div. 6-554.3-M15 

131. Calibration Measurements on MIT Crystal Hydro- 
phones HK-35, XMS-3Y, XMS-5, XMS-6, HKA- 
57, HKC-59, and XMQ-1, D. Bernard Simmons, 
NDRC 6.1-sr20-599, USRL, Jan. 6, 1943. 

Div. 6-554.3-M18 

132. Comparison of Piezoelectric and Magnetostric- 

f 


tion Hydrophones for Sonic Listening, James W. 
Follin, Jr., Report G27/130, NDRC 6.1-sr20-653, 
CUDWR-NLL, Mar. 21, 1943. Div. 6-554-M19 

133. Calibration of Standard Practice Target Trans- 

ducers BDl-32 #337 and CDl-21 #283, Frank 
H. Graham, NDRC 6.1-sr20-614, USRL, Mar. 30, 
1943. Div. 6-554.4-M5 

134. Charactey'istics of Some Transducers Made by 

UCDWR, NDRC 6.1-sr30-848, Report U23, 
UCDWR, May 6, 1943. Div. 6-554-M20 

135. Calibration of San Diego Crystal Transceiver 

GA2-2 #355, Eginhard Dietze, NDRC 6.1-sr20- 
873, USRL, May 18, 1943. Div. 6-554.4-M6 

136. Measurements on CH 10, No. 38U Crystal Trans- 

ducer, Edward Gerjuoy, Report D41/354, CUDWR- 
NLL, May 22, 1943. Div. 6-554-M23 

137. Calibration Data on Eight ERSB Hydrophones, 
Edward Gerjuoy, Ralph R. MacLaughlin, Report 
D16/472, CUDWR-NLL, Aug. 11, 1943. 

Div. 6-554.2-M12 

138. Measurements on Magnetostriction Transducer 

COG-50153, C. J. Burbank, Report C17, UCDWR, 
Nov. 8, 1943. Div. 6-554.2-M13 

139. Measurements of 5-inch Straight Toroidally 

Wound Hydrophones, Evaluation of Annealing 
of Nickel II, Wilbur T. Harris, Ralph R. Mac- 
Laughlin, and Edward Gerjuoy, Report D16/610, 
CUDWR-NLL, Nov. 11, 1943. Div. 6-554.2-M14 

140. Measurements on Crystal Transducer CS2-3 

#1122, C. J. Burbank, Report C24, UCDWR, 
Nov. 19, 1943. Div. 6-554.3-M34 

141. Calibration of A2U, A25, and A27 Toroidally- 
Wound Straight Magnetostriction Hydrophones, 
Frank H. Graham and D. Bernard Simmons, 
NDRC 6.1-srll30-1193, USRL, Dec. 17, 1943. 

Div. 6-554.2-M15 

Calibration of Magnetostriction Hydrophone 
COG 51053 #62, L. Pauline Leighton, Erwin 
Shrader and Leslie L. Foldy, NDRC 6.1-srll30- 
1363, USRL, Feb. 2, 1944. Div. 6-554.2-M17 
Calibration of a GBL-2 Crystal Hydrophone, 
David W. Van Lennep, Report G12/914, CUDWR- 
NLL, May 10, 1944. Div. 6-554.3-M39 

Relative Pressure Measurement in Shock Waves 
from Small Underwater Explosives, M. F. M. 
Osborne and A. H. Taylor, Report S-2305, NRL, 
June 10, 1944. Div. 6-551-Mll 

Calibration of MIT Crystal Projector XPA, 
L. Pauline Leighton, NDRC 6.1-srll30-1631, 
USRL, June 29, 1944. Div. 6-553.2-M8 

Calibration of CYJf-35 Crystal Hydrophone Serial 
#1235, L. Pauline Leighton, NDRC 6.1-srll30- 
1637, USRL, July 17, 1944. Div. 6-554.3-M42 
Calibration of Tourmaline Hydrophone #529 
Manufactured by the Stanolind Oil & Gas Com- 
pany, Frank H. Graham, NDRC 6.1-srll30-1828, 
USRL, Sept. 8, 1944. Div. 6-554.3-M43 

Calibration of NL130 Hydrophones #H191 and 
#H193, L. Pauline Leighton, NDRC 6.1-srll30- 


142. 

143. 

144. 

145. 

146. 

147. 


148. 



348 


BIBLIOGRAPHY 


149. 

150. 

151. 

152. 

153. 

154. 

155. 

156. 

157. 

158. 

159. 

160. 

161. 

162. 

163. 

164. 


1838, USRL, Oct. 19, 1944. Div. 6-554-M36 

Calibration of Stanolind Oil & Gas Company 
Tourmaline Gauges, Eginhard Dietze, NDRC 6.1- 
srll30-1971, USRL, Oct. 31, 1944. 

Div. 6-554.3-M44 
Double Hydrophone-Baffle Assembly with Im- 
proved Directivity. Barge Measurements of Direc- 
tivity Index, Wilbur T. Harris and David W. 

Van Lennep, Report G12/1218, CUDWR-NLL, 

Nov. 6, 1944. Div. 6-552-M14 

Calibration of NLl2Jf Hydroj)hone (CQA-5107Jf) 
with NL129-A Baffle, Eginhard Dietze and Gene- 
vieve D. Weldon, NDRC 6.1-srll30-2135, USRL, 
Feb. 12, 1945. Div. 6-554-M37 

Calibration of UCDWR Frequency Modulated 
Sonar, Leslie L. Foldy, NDRC 6.1-srll30-2139, 
USRL, Feb. 24, 1945. Div. 6-556-Ml 

The Dependence of the Operational Efficacy of 
Echo-Ranging Gear on its Physical Character- 
istics, Henry Primakoff and Martin J. Klein, 
NDRC 6.1-srll30-2141, USRL, Mar. 15, 1945. 

Div. 6-551-M14 

The Directional Radio Sono Buoy, OSRD 5279, 
NDRC 6.1-srll28-2224, CUDWR-NLL, May 20, 
1945. Div. 6-624.2-M7 

Cable Connected Hydrophone Systems, William 
B. Snow, Henry B. Hoff and A. M. Berry, OSRD 
5243, NDRC 6.1-srll28-1946, CUDWR-NLL, May 
21, 1945. Div. 6-625.1-M9 

The Model JT Sonar Equipment, C. R. Sawyer, 
OSRD 5275, NDRC 6.1-srll28-2215, Report D55/ 
1069, CUDWR-NLL, May 25, 1945. 

Div. 6-623.2-M7 

The XMX Hydrophone, NDRC 6.1-srl046-2036, 
MIT-USL, May 31, 1945. Div. 6-553.1-M8 

The XPA Crystal Transducer, NDRC 6.1-srl046- 
2041, MIT-USL, June 30, 1945. 

Div. 6-553.2-Mll 
The Acoustic Shielding Effect of Baffles, Joseph 
B. Keller, Martin J. Klein, and Henry Primakoff, 
NDRC 6.1-srll30-2299, USRL, July 13, 1945. 

Div. 6-552-M19 

XQHA Projector #8 — Effects of Protective 
Sheath and of Hydrostatic Pressure, Eginhard 
Dietze, NDRC 6.1-srll30-2301, USRL, July 20, 
1945. Div. 6-554.1-M6 

Calibration of XQHA Scanning Sonar, Leslie L. 
Foldy, NDRC 6.1-srll30-2S70, USRL, Sept. 10, 
1945. Div. 6-554.4-M13 

Experimental 3^2 Layer XQHA Transducer, 
Genevieve D. Weldon and Frank H. Graham, 
NDRC 6.1-srll30-2372, USRL, Sept. 18, 1945. 

Div. 6-554.4-M14 
Visual Recognition Differential on the PPI 
Screen, Earle C. Gregg, Jr., and B. English, 
NDRC 6.1-srll30-2378, USRL, Oct. 17, 1945. 

Div. 6-551-M15 

Analytical Calculation of Coverage Rates for 
Scanning Sonar and Searchlight Gear, Joseph B. 


Keller, NDRC 6.1-srll30-2379, USRL, Oct. 24, 
1945. Div. 6-551-M16 

CHAPTER 7 

165. Preliminay'y Calibration of Brush Crystal Hydro- 
phones — Model ClO-Al, Frank H. Graham, Re- 
port 2240, BTL, Oct. 18, 1941. Div. 6-554.3-Ml 

166. Calibrations of Semmes Hydrophone, Donald P. 

Loye, Report G12/1818, CUDWR-NLL, Jan. 8, 
1942. Div. 6-554-M6 

167. Preliminary Calibration of XEl-2 Serial Nos. 6 
and 7 Crystal Hydrojjhones, Eginhard Dietze, 
Report 2420, BTL, Mar. 17, 1942. 

Div. 6-554.3-M4 

168. Test on Model of Working Standard Projector 

for 25-100 KC Frequency Range, Frank H. 
Graham and Eginhard Dietze, USRL, May 25, 
1942. Div. 6-553.2-M2 

169. Tests on 100 KC Proximity Fuze, Eginhard 
Dietze, NDRC C4-sr20-106, USRL, June 5, 1942. 

Div. 6-554.4-Ml 

170. Characteristics of Portable Supersonic Prism for 
Offshore Ship Location, Eginhard Dietze and 
William F. Offutt, USRL, June 12, 1942. 

Div. 6-553.3-Ml 

171. Calibration Measurements on Brush Crystal 

Hydrophones XEl-2 #5 and C23-1 #2, Frank H. 
Graham, NDRC C4-sr20-114, USRL, June 20, 
1942. Div. 6-554.3-M6 

172. Directional Patterns of Sample C-26 Sound 

Ti'ansceiver built by Brush Develop^nent Com- 
pany, Ray S. Alleman, Report D6/3368, CUDWR- 
NLL, July 10, 1942. Div. 6-554-M13 

173. Calibration Measurements on Submarine Signal 
Company Crystal Hydrophones SS-6-B, SS-6-P, 
S-12Jf #1, S-12U #2, Frank H. Graham, NDRC 
C4-sr20-144, USRL, July 13, 1942. 

Div. 6-554.3-M7 

174. Calibration Measurements of Three Special Mag- 

netostriction Hydrophones from Bell Telephone 
Laboratories, Frank H. Graham, NDRC C4-sr20- 
151, USRL, Aug. 4, 1942. Div. 6-554.2-M5 

175. Calibration Measurements on Three Intermediate 
Frequency Projectors Nos. 2, U, and 5, Covering 
the Frequency Range from 7 to 30 Kilocycles, 
Norma Bailey and Frank H. Graham, NDRC 
C4-sr20-152, USRL, Aug. 4, 1942. 

Div. 6-553.2-M4 

176. Calibration Measurements of Four-Foot Rubber- 

Covered Magnetostriction Hydrophone as a 
Hydrophone and as a Projector, William F. Offutt 
and Frank H. Graham, NDRC C4-sr20-196, 
USRL, Aug. 15, 1942. Div. 6-554.2-M6 

177. Characteristics of Supersonic Prism PALc In- 
tended for Offshore Ship Location, William F. 
Offutt, NDRC C4-sr20-198, USRL, Aug. 18, 1942. 

Div. 6-553.3-M2 

178. Calibration of Two RCA Magnetostriction Hydro- 
phones in the Mark 9 Depth Charge Container, 


G 


CONFIDENTIA 


BIBLIOGRAPHY 


349 


179. 


180. 


181. 


182. 


183. 


184. 


185.- 


186. 


187. 


188. 


189. 


190. 


191. 


i92. 


Frank H. Graham and Norma Bailey, NDRC 
C4-sr20-200, USRL, Aug. 24, 1942. 

Div. 6-554.2-M7 

Measurements of Sound Transmission through 
Single and Double Plates, Frank H. Graham, 
NDRC C4-sr20-201, USRL, Aug. 29, 1942. 

Div. 6-551-M5 

Characteristics of Supersonic Prism PA2 In- 
tended for Offshore Ship Location, William F. 
Offutt, NDRC C4-sr20-281, USRL, Sept. 15, 1942. 

Div. 6-553.3-M3 

Calibration Measurements of the Brush AX6 and 
CUU Dual Pattern Crystal Hydrophones, Frank 
H. Graham, NDRC C4-sr20-285, USRL, Sept. 30, 
1942. Div. 6-554.3-M13 

Calibration .Measurements on Brush Crystal 
Hydrophones C23-#355, C37-ff:l, AX10-#U, and 
AXlO-#5, Leslie L. Foldy, NDRC C4-sr20-286, 
USRL, Oct. 5, 1942. Div. 6-554.3-M14 

Effect of Painting Diaphragm of RCA QC Pro- 
jector Serial No. 25, Frank H. Graham, NDRC 
C4-sr20-290, USRL, Oct. 26, 1942. 

Div. 6-554. 1-M2 

Calibration Measurements on NOL Standards SV 
#1 and #2: RCA Hydrophone 2 A #If7; and 
Brush Development Company Hydrophone C21 
A2 #9, Leslie L. Foldy and Eginhard Dietze, 
OSRD 978, NDRC C4-sr20-291, USRL, Oct. 27, 
1942. Div. 6-553.1-M3 

General Electric Company Inertia Type Carbon 
Hydrophone Nos. 1 & 2, Eginhard Dietze, NDRC 
C4-sr20-293, USRL, Nov. 12, 1942. 

Div. 6-554-M14 

Calibration Measurements of Bell Telephone 
Laboratories' 5A Hydrophone, D. Bernard Sim- 
mons, NDRC C4-sr20-297, USRL, Nov. 16, 1942. 

Div. 6-554-M16 

Calibration Measurements on Brush AX-6-F 
Dual Pattern Crystal Hydrophones, Norma 
Bailey and Eginhard Dietze, NDRC C4-sr20-299, 
USRL, Nov. 26, 1942. Div. 6-554.3-M16 

Calibration of Bell Telephone Laboratories' 10 
Kilocycle Transceiver Units Nos. 1 and 2, Egin- 
hard Dietze, NDRC C4-sr20-592, USRL, Dec. 10, 
1942. Div. 6-554.4-M2 

Calibration of Dual Pattern AX-3C Hydrophones 
and of C17 Hydrophone Mounted on Test Pot 
Mark 15, Eginhard Dietze, NDRC C4-sr20-594, 
USRL, Dec. 15, 1942. Div. 6-554.4-M3 

Listening Systems for Patrol Craft (A Multi- 
Purpose Hydrophone for Listening Systems), 
NDRC 6.1-sr692-661, BTL, Dec. 15, 1942. 

Div. 6-554-M17 

Calibration Measurements on Crystal Hydro- 
phone Cll-2 #11 with Redesigned Special Naval 
Ordnance Laboratory Preamplifier, Norma Bailey, 
NDRC C4-sr20-596, USRL, Dec. 18, 1942. 

Div. 6-554.3-M17 
Electrical Impedance of MIT Rochelle Salt Hydro- 

\ 


phones, MIT Research Project DIC 5985, Report 
Series Al, No. 9, MIT-USL, Jan. 25, 1943. 

' Div. 6-554.3-M19 

Calibration of BriLsh Dual Pattern AX-Jf7 & AX- 
U7-1 Crystal Hydrophones, Norma Bailey, NDRC 
6.1-sr20-610, USRL, Mar. 9, 1943. 

Div. 6-554.3-M20 

Calibration of BTL 20 KC and UO KC Transceiver 
Units #1 and #2, Eginhard Dietze, NDRC 6.1- 
sr20-613, USRL, Mar. 29, 1943. 

Div. 6-554.4-M4 

Calibration of Brush Crystal Hydrophones CA3 
#5 and #11 and Thuras Magnetostriction Hydro- 
phones Type D-16 Mark IV-D #1 and #2, Egin- 
hard Dietze, D. Bernard Simmons, NDRC 6.1- 
sr20-871, USRL, May 14, 1943. Div. 6-554-M21 
Measurements of AX-58 Hydrophones, Edward 
Gerjuoy, Report G27/353, CUDWR-NLL, May 
21, 1943. Div. 6-554.3-M22 

Calibration of Five C-50 Type Hydrophones, 
Frank H. Graham, NDRC 6.1-sr20-880, USRL, 
June 19, 1943. Div. 6-554-M26 

Measurements of AX-50 Hydrophones, Edward 
Gerjuoy, Report G12/408, CUDWR-NLL, June 
30, 1943. Div. 6-554.3-M24 

Calibration of Three D-16 IV-D Magnetostric- 
tion Hydrophones Serial Numbers 38, 98, and 
105, Frank H. Graham, NDRC 6.1-sr20-885, 
USRL, July 7, 1943. Div. 6-554.2-Mll 

Calibration of General Electric Company Inertia 
Type Carbon Hydrophone Units Nos. 3, U, 5, and 
32, D. Bernard Simmons, NDRC 6.1-sr20-940, 
USRL, July 17, 1943. Div. 6-554-M27 

Calibration Tests on an RCA IV Permanent 
Magnet Echo-Ranging Projector Model #3 in a 
WEA-2 Dome, Eginhard Dietze, NDRC 6.1-sr20- 
944, USRL, July 23, 1943. Div. 6-555-M8 

Calibration of Brush Crystal Hydrophone AX58 
#6, Frank H. Graham, NDRC 6.1-sr20-949, 
USRL, Aug. 17, 1943. Div. 6-554.3-M25 

Calibration of HT-1 Tourmaline Crystal Hydro- 
phone and Cll-Al #22 Rochelle Salt Crystal 
Hydrophone, D. Bernard Simmons, NDRC 6.1- 
sr20-952, USRL, Aug. 30, 1943. 

Div. 6-554.3-M26 

204. Measurements of AX-58 No. 6 Brush Crystal 
Hydrophones, Edward Gerjuoy, Report G12/554, 
CUDWR-NLL, Oct. 19, 1943. Div. 6-554.3-M27 

205. Calibration of AX50 #2 and AX50 #3 Crystal 
Hydrophones, D. Bernard Simmons, NDRC 6.1- 
srll30-1181, USRL, Oct. 22, 1943. 

Div. 6-554.3-M28 

206. Calibrated Subaqueous Microphones, H. F. Olson, 
J. Preston, RCA Laboratories, Oct. 26, 1943. 

207. Calibration of Several Brush C-11 Hydy'ophone 
Units Used with Naval Ordnance Laboratory 
Mark 3 Acoustic System, L. Pauline Leighton, 
NDRC 6.1-srll30-1182, USRL, Oct. 27, 1943. 

Div. 6-554.3-M29 


LONFIDENTIAi 


193. 

194. 

195. 

196. 

197. 

198. 

199. 

200 . 

201 . 

202 . 

203. 



BIBLIOGRAPHY 


350 


208. Measurement of C-26 Transducer, Edward Ger- 
juoy and David W. Van Lennep, Report G13/882, 
CUDWR-NLL, Dec. 29, 1943. Div. 6-554-M31 

209. Calibration of Brush AX68 and CU5-C #1 
Crystal Hydrophones, D. Bernard Simmons, 
NDRC 6.1-srll30-1184, USRL, Nov. 11, 1943. 

Div. 6-554.3-M32 

210. Calibration of Brush AX57 #2 ADP Crystal 

Hydrophone and AX7U #1, C^O-l #175, C37-5 
#72 Rochelle Salt Crystal Hydrophones, D. Ber- 
nard Simmons, NDRC 6.1-srll30-1185, USRL, 
Nov. 12, 1943. Div. 6-554.3-M33 

211. Measurements of C-26-1, No. U Crystal Trans- 

ducer, Edward Gerjuoy, Report G13/710, CUDWR- 
NLL, Jan. 19, 1944. Div. 6-554-M32 

212. Measurements of AX50, No. 2, and AX50, No. 3 
Hydrophone, Edward Gerjuoy, Report G12/583, 
CUDWR-NLL, Nov. 1, 1943. 

Div. 6-554.3-M31 

213. Calibration of Sound Meter and Hydrophone, 

Robert A. Wagner, Report P42/787, CUDWR- 
NLL, Mar. 9, 1944. Div. 6-554-M33 

214. Calibration of AX-105 #1 and #2 Transducers 
with EN-1 Noise Generator, Eginhard Dietze, 
NDRC 6.1-srll30-1371, USRL, Mar. 24, 1944. 

Div. 6-554.3-M37 

215. Calibration of CU9-1 Hydrophones in Mark 13-5 
Mine Case, L. Pauline Leighton, NDRC 6.1- 
srll30-1372, USRL, Mar. 30, 1944. 

Div. 6-554.4-M7 

216. Calibration of Brush AX68 #4 and CU5-C #1 
Crystal Hydrophones (Addendum to Report No. 
6.1-sr20-1181t.), Eginhard Dietze, NDRC 6.1- 
srll30-1624, USRL, May 26, 1944. 

Div. 6-554.3-M40 

217. Calibration of RCA Laboratories USDAR 1000 

Units #1 and #2, Earle C. Gregg, Jr., and Egin- 
hard Dietze, NDRC 6.1-srll30-1632, USRL, June 
30, 1944. Div. 6-554.4-M8 

218. Calibration of RCA Laboratories USDAR 500 
Unit #1, L. Pauline Leighton, NDRC 6.1-srll30- 
1821, USRL, Aug. 15, 1944. 

Div. 6-554.4-M9 


219. Calibration of RCA Laboratories USDAR 250 

Unit Serial #1, L. Pauline Leighton, Joseph B. 
Keller, NDRC 6.1-srll30-1822, USRL, Aug. 18, 
1944. Div. 6-554.4-MlO 

220. Comparison of Acoustic Properties of QCU 
Baffles Manufactured by the Edward G. Budd 
Manufacturing Company, Eginhard Dietze, 
NDRC 6.1-srll30-1823, USRL, Aug. 21, 1944. 

Div. 6-555-M25 

221. Final Report on Listening Systems for Patrol 
Craft, NDRC 6.1-sr692-1698, BTL, Dec. 1, 1944. 

Div. 6-622.1-M5 

222. Calibration of RQ-51055 (AX-58 A) Hydrophones 
to be Employed with OAY Sound Meters. Com- 
parison of Two Methods, David W. Van Lennep, 
Report D53/1271, CUDWR-NLL, Dec. 7, 1944. 

Div. 6-554.3-M45 

223. Calibration of C37 Hydrophone, Eginhard 
Dietze and L. Pauline Leighton, NDRC 6.1- 
srll30-2130, USRL, Jan. 31, 1945. 

Div. 6-554.3-M46 

224. Non-Directional Magnetostriction Transducer, 
NDRC 6.1-srl097-1328, BTL, Feb. 1, 1945. 

Div. 6-554.2-M18 

225. Calibration of RCA lA" ADP Crystal Projector 

and QCU -2 Dome, Eginhard Dietze and Genevieve 
D. Weldon, NDRC 6.1-srll30-2140, USRL, Feb. 
26, 1945. Div. 6-555-M27 

226. The AX-U8-A ADP Crystal Hydrophone, William 

B. Snow, Report G12/1417, CUDWR-NLL, Feb. 
28, 1945. Div. 6-554.3-M48 

227. Calibrations of Three AX-120 Hydrophones, Wil- 

liam B. Snow, Report G12/1419, CUDWR-NLL, 
Feb. 28, 1945. Div. 6-554.3-M47 

228. Calibration of Projector for Underwater Object 
Locator Equipment (UOL), Eginhard Dietze, 
NDRC 6.1-srll30-2302, USRL, July 23, 1945. 

Div. 6-554.4-M12 

229. Calibration of Submarine Signal Company QGC 
Projector, Eginhard Dietze, NDRC 6.1-srll30- 
2306, USRL, Aug. 13, 1945. Div. 6-554.1-M7 




CONTRACT NUMBERS, CONTRACTORS, AND SUBJECT OF CONTRACTS 


Contract 

Numbers 

Name and Address of Contractor 

/ 

Subject 

OEMsr-212 

Western Electric Company (for Bell Tele- 
phone Laboratories, Inc.) 

120 Broadway, New York, N. Y. 

Studies and experimental investigations in 
connection with the development, con- 
struction and calibration of hydrophonic 
standard receivers and projectors and 
establish and operate field stations neces- 
sary for the maintenance of a calibration 
system. 

OEMsr-20 

The Trustees of Columbia University in the 
City of New York 

New York 27, New York 

Studies and investigations and the develop- 
ment of methods and equipment pertain- 
ing to submarine warfare. 

OEMsr-1130 

The Trustees of Columbia University in the 

Studies and experimental investigations in 


City of New York 

New York 27, New York 

connection with the testing and calibra- 
tion of acoustic devices including opera- 
tions of underwater sound reference test 
laboratories. 

OEMsr-783 

Western Electric Company (for Bell Tele- 
phone Laboratories, Inc.) 

120 Broadway, New York, N. Y. 

Studies and investigations in connection 
with the development of calibration de- 
vices and methods in the fields of hydro- 
phonics, etc. 

OEMsr-1189 

Western Electric Company (for Bell Tele- 
phone Laboratories, Inc.) 

120 Broadway, New York, N. Y. 

Manufacture, stocking and repair of hydro- 
phonic apparatus. 



FIDENTI 


351 


SERVICE PROJECT NUMBERS 

The projects listed below were transmitted to the Executive 
Secretary, NDRC, from the Navy Department through the 
Office of Research and Inventions (formerly the Coordinator 
of Research and Development), Navy Department. 


Service 


Project 

Subject 

Number 


NS-139 

Testing and calibrating facilities. 

NS-182 

Projector requirements and test limits. 


352 


HYDROPHONE ADVISORY COMMITTEE 


The Hydrophone Advisory Committee was the name which soon came to be used for the Committee on Standards 
and Calibration appointed by the Coordinator of Research and Development, April 1942, for the following purpose: 
to assist in establishing calibration techniques, reference levels, and standard definitions and terms to be used 
generally by all groups making underwater sound measurements of interest to the Navy. 

Shortly after the organization of this committee. Dr. Robert S. Shankland was selected to be its chairman. 
While from time to time the personnel of the committee changed, in general the following organizations were 
represented at meetings and were otherwise active: 

OflEice of the Coordinator of Research and Development (now Office of Research and Inventions) 

Bureau of Ships (940) 

Naval Ordnance Laboratory 
Naval Research Laboratory 
Division 6: 

Columbia University Division of War Research at the U. S. Navy Underwater Sound Laboratory, Harvard 
Underwater Sound Laboratory, Massachusetts Institute of Technology Underwater Sound Laboratory, 
University of California Division of War Research at the U. S. Navy Radio and Sound Laboratory, Under- 
water Sound Reference Laboratories of Columbia University Division of War Research. 

Bell Telephone Laboratories, Inc. 

Brush Development Company 
Radio Corporation of America 
Submarine Signal Company 



353 







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INDEX 


The subject indexes of all STR volumes are combined in a master index printed in a separate volume. For 
access to the index volume consult the Army or Navy Agency listed on the reverse of the half-title page. 


A-24 hydrophone, 347 
A-25 hydrophone, 347 
A-27 hydrophone, 347 
ADP crystal transducers 
5A projector, 6-7 
AX-48-A hydrophone, 350 
AX-57 hydrophone, 350 
AX-63 projector, 138, 284-285 
AX-70 projector, 8-9 
AX-91 hydrophone, 30-31 
AX114A hydrophone, 290-291 
AX-124 projector, 8-9 
AX-128 transducer, 292-293 
J Q sonar-listening hydrophone, 
modified, 62-63 

QB type projector (BTL), 136- 
137 

QB type projector (SK 5982), 
146-147 

QJB sonar-ranging projector, 
122-123 

RCA projector, 144-145 
WFA-1 topside transducers, 148- 
151 

X-5 projector, 140-141 
X-6 projector, 142-143 
ADP crystal transducers, Z-cut 
3A hydrophone, 28-29 
CJJ-78256 serial 20 sound head, 
226-227 

EP2Z transducer, 230-231 
FE2Z transducer, 232-233 
GD34Z-1 transducer, 238-239 
ADP crystals 
advantages, 3 
in Asdic transducers, 176 
in U. S. Navy experimental units, 
136-151 

in USRL standard transducers, 2 
Ammonium dihydrogen phosphate 
crystals 

see ADP crystals 

Antisubmarine operations, scan- 
ning sonar, 270-274 
attack, 270 
chase, 270-271 
detection, 270-273 
Asdic sonar equipment, 176-185 
A/S 95 oscillator, 176, 178 
A/S 96 oscillator, 176, 178-179 
type 135 set, 180-183 
type 150 transducer, 184-185 
Astatic Corporation 
JP hydrophone, 212-213 
NL-130 hydrophone, 216-217 


AX-3C hydrophone, 349 
AX-6 hydrophone, 304 
AX-6F hydrophone, 304 
AX-10 hydrophone, 300 
AX-47 hydrophone, 278-279 
AX-47-1 hydrophone, 278-279 
AX-48A hydrophone, 350 
AX-50 hydrophone, 280-281 
AX-57 crystal hydrophone, 350 
AX-58 hydrophone, 282 
AX-58A hydrophone, 282-283 
AX-63 projector, 138, 284-285 
AX-68 crystal hydrophone, 350 
AX-70 projector, 3, 8-9 
AX-75 hydrophone, reduction of 
coupling loss, 275 
AX-79 hydrophone, 286 
AX-79-1 hydrophone, 286-287 
AX-83 hydrophone, 288-289 
AX-91 hydrophone, 30-31 
AX-102-1 projector, 144 
AX-105 transducer, 350 
AX-114A hydrophone, 290-291 
AX-120 hydrophone, 350 
AX-124 projector, 3, 8-9 
AX-128 transducer, 292-293 
AX-131 transducer, 294-295 

B1 hydrophone, 192 
B19B hydrophone, 4, 32-33 
B19H monitor hydrophone, 34-35 
Baffles for magnetostrictive trans- 
ducers, 205 

BBl-32 standard practice target 
transducer, 347 

Bearing accuracy of XQHA system, 
261 

Bell Telephone Laboratories 
lA hydrophone, 24-25 
IK projector, 18-19 
2A hydrophone, 26-27 
2B projector, 10-11 
3A hydrophone, 28-29 
3B projector, 12-13 
4A cable hydrophone, 310-311 
4B projector, 14-15 
5 A projector, 6-7 
5C hydrophone, 36-39 
5E hydrophone, 36-39 
6B projector, 16-17 
7A hydrophone, 314-315 
8A hydrophone, 316-317 
9A hydrophone, 318-319 
10 kc, 20 kc, 40 kc transceiver 
units, 322-323 


ESO 572081 hydrophone, 343 
hydrophone standards, compari- 
son, 4 

MH transducers, 22-23 
nondirectional magnetostriction, 
320-321 

projector standards, comparison, 
1-3 

QB-type ADP projector, 136-137 
QBF sonar-ranging projector, 
86-87 

QJB sonar-ranging projector, 
122-123 

sonar equipments, 276, 310-323 
standard transducers used by 
USRL, 1-49 

WFA-1 topside transducer, 148- 
151 

British sonar equipment 

see also Asdic sonar equipment 
HT-1 hydrophone, 186-187 
low frequency standard hydro- 
phone, 190-191 
type P hydrophone, 188-189 
British type dome 

Submarine Signal Co. dome, 162, 
165 

882A dome, 162 

Brush Development Company, 3 
AX-6 hydrophone, 304-305 
AX-6-F hydrophone, 304-305 
AX-47 hydrophone, 278-279 
AX-47-1 hydrophone, 278-279 
AX-50 hydrophone, 280-281 
AX-58A hydrophone, 282-283 
AX-63 projector, 138, 284-285 
AX-68 hydrophone, 350 
AX-70 projector, 8-9 
AX-79 hydrophone, 286-287 
AX-79-1 hydrophone, 286-287 
AX-83 hydrophone, 288-289 
AX-91 hydrophone, 30-31 
AX-114A hydrophone, 290-291 
AX-124 projector, 8-9 
AX-128 transducer, 292-293 
AX-131 transducer, 294-295 
CIO hydrophone, 296-297 
Cll-Al hydrophone, 40-41 
C13 transducer, 20-21 
C21-A2 hydrophone, 349 
C23 hydrophone, 298-299 
C26 transceiver, 348 
C35 hydrophone, 345 
C37 hydrophone, 300-301 
C37-5 hydrophone, 350 


CONFIDENTIAL 


355 


356 


INDEX 


C43 hydrophone, 302-303 
C44 hydrophone, 304-305 
C45-C hydrophone, 350 
C49 hydrophone, 306-307 
C50 hydrophone, 308-309 
JO parabolic hydrophone, 56-57 
JQ sonar-listening equipment, 
60-61 

JQ sonar-listening hydrophone, 
modified, 62-63 

BTL 

see Bell Telephone Laboratories 
Budd domes, 162 
Bureau of Ordnance, 194 
Bureau of Ships, 194 

CIO hydrophone, 296-297 
Cll hydrophone, 276 
Cll-Al hydrophones, 40-41 
Cll-2 crystal hydrophone, 349 
C13 transducer, 3, 20-21 
C17 hydrophone, 349 
C21-A2 hydrophone, 346, 349 
C23 hydrophone, 288, 298-299 
C26 transceiver, 348, 350 
C35 hydrophone, 345 
C36 hydrophone, 56-57 
C37 hydrophone, 300-301 
C37-5 hydrophone, 300, 350 
C37-6 hydrophone, 300 
C43 hydrophone, 302-303 
C44 hydrophone, 304-305 
C45-C crystal hydrophone, 350 
C49 hydrophone, 306-307 
C50 hydrophone, 308-309 
Calibration charts, transducer 
see names of individual trans- 
ducer models 
Canadian transducers 

see also Asdic sonar equipment 
NRE B1 hydrophone, 192 
NRE FI hydrophone, 193 
Capacity rotation sonar 

see CR sonar, XQHA system 
Carbon hydrophone. General Elec- 
tric, 337 

Castor oil, use in sonar transducers, 
275 

CBD 51035 hydrophone, 56-57 
CBD 51052 hydrophone, 60-63 
CBM 78016A projector, 70-73 
CBM 78017 projector, 90-91 
CBM 78067 projector, 70-71 
CBM 78098 projector, 98 
CBM 78099 projector, 92-93 
CBM 78115 projector, 100-102 
CBM 78138 projector, 66-67 
CBM 78139 projector, 68-69 
CBM 78142 projector, 82-83 
CBM 78142A projector, 84-85 


CBM 78145 projector, 108-109 
CBM 78146 projector, 108 
CBM 78153 projector, 124-126 
CBM 78154 projector, 124 
CBM 78155 projector, 124 
CBM 78156 projector, 134-135 
CBM 78164 (900A) projector, 110 
CBM 78164A (900E) projector, 

110-113 

CBM 78165 (900) projector, 110 
CBM 78165A (900D) projector, 110 
CBM 78182 projector, 98-99 
CBM 78183 projector, 94-95 
CBM 78184 projector, 103-105 
CBM 78185 projector, 106-107 
CBM 78203 projector, 78-79 
CBM 78212 projector, 127-129 
CBM 78213 projector, 130-131 
CBM 78214 projector, 80-81 
CBM 78220 projector, 116-117 
CBM 78221 projector, 118-119 
CDl-21 transducer, 347 
CFF 78187 projector, 88-89 
CH-10 transducer, 347 
CIP 78138 projector, 66-67 
CIP 78139 projector, 68-69 
CJJ 78256 serial 20 sound head, 
226-227 

CMF condenser hydrophone, 1, 4, 
42-43 

COG 51053 hydrophone, 212-213 
Columbia Univ. Div. of War Re- 
search, 204-208 

JP sonar-listening equipment, 58 
JT sonar-listening equipment, 64 
Condenser hydrophones 
2A hydrophone, 326-327 
CMF hydrophone, 1, 4, 42-43 
for frequencies below 75 cps, 343 
Corrugated dome, 162, 163 
CQA 51074 hydrophone, 214-215 
CR sonar, XQHA system, 249-261 
bearing accuracy, 261, 270-271 
calibration charts, 255-260 
coverage rate, 272-273 
description of system operation, 
250-254 

directivity index, 254, 271 
dynamic scanning directivity 
pattern, 261 

operational effectiveness, 270-274 
projector efficiency, 254 
scanning directivity pattern, 261 
visual and aural recognition 
differentials, 271 
CRV 78103 projector, 96-97 
CRV 78104 projector, 96-97 
CRV 78133 projector, 74-75 
CRV 78151 projector, 132-133 
CRV 78169 projector, 76-77 



CRV 78170 projector, 76-77 
CRV 78208 projector, 120 
CRV 78209 projector, 120 
CRV 78210 projector, 120-121 
CRV 78211 projector, 120 
CRV 78225 projector, 114-115 
Crystal transducers 

see also ADP crystal trans- 
ducers; Rochelle salt crystal 
transducers; Tourmaline 
crystal transducers 
efficiency, 204 
impedance, 205 

use of ADP crystals, 2, 3, 136- 
151, 176 

use of quartz crystals, 176, 241 
use of rochelle salt crystals, 2, 3, 
176 

use of tourmaline crystals, 176, 
241 

Crystal transducers, specific 
models 

2VLF hydrophone, 343 
5D-1 hydrophone, 344 
AX-68 hydrophone, 350 
Cll-2 hydrophone, 349 
C35 hydrophone, 345 
C45-C hydrophone, 350 
CH-10 transducer, 347 
CS2-3 transducer, 347 
CY4-35 transducer, 347 
ESO 572081 hydrophone, 343 
GBL-2 hydrophone, 347 
XE 1-2 hydrophone, 348 
XMQ hydrophone, 347 
XMS hydrophone, 343, 347 
CS2-3 crystal transducer, 347 
CW 78178 projector, 86-87 
CW 78207 projector, 122-123 
CY4 sample 3 A transducer, 228- 
229 

CY4-35 crystal hydrophone, 347 
Cylindrical hydrophone, toroidally 
wound, 205, 208 

D-16 Mark IV-D hydrophone, 208, 
210-211 

David Taylor Model Basin, 194 
C21-A2 hydrophone, 346 
TMB tourmaline gauge, 242-243 
TMB-Tl hydrophone, 244-245 
Depth charge container, Mark 9, 
hydrophone calibration, 348 
Depth determining transducers, 
152-153 

Directional properties of individual 
transducers 

see na7ne of individual trans- 
ducer model 


INDEX 


357 


Division 6.1 underwater acoustic 
instruments 

Harvard instruments, 32-35, 154- 
155, 208, 249-274 

MIT instruments, 208-209, 222- 
225 

New London hydrophones, 204- 
208, 210-221 
scanning sonar, 249-274 
tourmaline gauges, 241-248 
UCDWR instruments, 209, 226- 
239 

Domes, 160-175 
baffles, 161 

description and calibration of 
representative types, 162 
design, 161 

directivity patterns, 161, 166-175 
performance characteristics, 50 
requirements, 160 
specular reflections, 160-162 
transmission loss, 160-162, 174 
Domes, types 

54 in. dome, 162, 172 
57 in. Budd dome, 162 
NRL corrugated dome, 162 
No. 892 dome, 172 
QBF type, 164-165, 170-171, 174- 
175 

QC spherical dome, 165 
QCU type, 164-168, 174 
QGA type, 164-166, 173-174 
WEA-1 dome, 165, 168-170, 175 
Dynamic scanning directivity pat- 
tern, 261 

Echo-ranging equipment, U. S. 

Navy, 53-54, 82-123 
Echo-sounding equipment, U. S. 

Navy, 51-52, 66-81 
Efficiency of various transducer 
models 

see name of individual trans- 
ducer model 
8A hydrophone, 316-317 
882A British dome, 162 
Electrodynamic hydrophone, RCA, 
328-329 

Electrodynamic projector. Sub- 
marine Signal Co., 156-157 
Electromagnetic transducers 
4A cable hydrophone, 310-311 
8A hydrophone, 316-317 
9A hydrophone, 318-319 
Electronic rotation sonar, 249-250, 
261 

Electrostatic hydrophones, 1, 4 
2A condenser hydrophone, 326- 
327 


CMF condenser hydrophone, 42- 
43 

EP2Z transducer, 230-231 
ER sonar, 249-250, 261 
ESO 572081 crystal hydrophone, 
BTL, 343 ' 

Expendable radio sono buoy trans- 
ducer, 210-211 

Explosive sound measurements, use 
of tourmaline gauges, 241 

FI hydrophone, 193 
FE2Z transducer, 232-233 
54 in. dome, 162, 172 
57 in. Budd dome, 162 
5A hydrophone, 312-313 
5A projector, 1, 2, 6-7 
5B hydrophone, 312 
5C hydrophone, 4, 36-39, 312 
5D-1 hydrophone, 344 
5E hydrophone, 3, 4, 36-39, 312 
FM sonar, 261-270 
analyzer, 264 

calibration test results, 264-270 
description of system operation, 
261-264 
indicator, 264 
oscillator, 262 
power amplifler, 262 
receiving circuit, 264 
sound head, 262-263 
Football-type transducer, 148-151 
40-kc transceiver unit, 322 
4A cable hydrophone, 310-311 
4A projector, 344 
4B projector, 1, 2, 14-15 
Freed Radio Corp, QBG sonar- 
ranging projector, 88-89 

GA2 transducer, 234-235 
GBL-2 crystal hydrophone, 347 
GD16-17 transducer, 236-237 
GD34Z-1 transducer, 238-239 
General Electric, 277 
carbon hydrophone, 337 
underwater object locator 
(UOL), 338-340 

GR-5 off-shore harbor defense unit 
hydrophone, 202 

GR-7 off-shore harbor defense unit 
hydrophone, 202 


Harbor defense hydrophone sys- 
tems, 202-203, 300-301, 310 
Harvard Underwater Sound Labo- 
ratory, 208 

B19-B hydrophone, 32-33 
B19-H hydrophone, 34-35 
CR scanning sonar, XQHA sys- 
tem, 249-261 


ONFIDEMTIAL 


ER scanning sonar, 249-250, 261 
HP laminated stack transducer, 
jl54-155 

sword arm depth angle trans- 
ducer, 152-153 

HK type hydrophone, 4, 44-45 
HKA hydrophone, 44 
HKB hydrophone, 44-45 
HKC hydrophone, 44-45 
HP hydrophone, 222 
HP-4 laminated stack transducer, 
154-155 

HT-1 hydrophone, 186-187 
HU hydrophone, 209, 223 
HU-9 magnetostriction hydrophone, 
343 

Hydrophone models 

see ADP crystal transducers; 
Magnetostriction trans- 
ducers; Rochelle salt crystal 
transducers; Tourmaline 
crystal transducers 
see also under names of indi- 
vidual models 
Hydrophone standards, 3-5 
see also Standard transducers 
directivity, 3 
impedance, 3 

response characteristics, 3-4 
shielding, 4 

Inertia type hydrophones, 347 

Japanese transducers, 345 
JK sonar-listening equipment, 50,. 
55, 82-83 

JO parabolic hydrophone assem- 
bly 56-57 

JP sonar-listening equipment, 58 
JP hydrophone, 212-213 
toroidal magnetostriction hydro- 
phone, 218-219 

JQ sonar-listening hydrophone, 60- 
63 

JT sonar-listening equipment, 64, 
208, 214-215 

K type hydrophone, 196-197 

Line hydrophones, magnetostriction 
see Magnetostriction transducers 
Listening equipment, sonar, 50 
see also under name of hydro- 
phone 

JK equipment, 55, 82-83 
JP equipment, 58, 212-213, 218- 
219 

JT equipment, 64, 208, 214-215 
Low frequency source, NOL, 2 


358 


INDEX 


Low frequency standard hydro- 
phone, 190-191, 343 
Low frequency standard projectors, 
343, 344, 348 

Magnetostriction transducers, 204- 
208 

baffles, 205 
efflciency, 204, 205 
frequency dependence of hydro- 
phone response, 204 
impedance, 205 
reduction of sidelobes, 205 
Magnetostrictive transducers, 
specific models 
A-24 hydrophone, 347 
A-25 hydrophone, 347 
A-27 hydrophone, 347 
Asdic, type 135; 180-183 
Asdic, type 150; 184-185 
B19-B hydrophone, 32-33 
B19-H hydrophone, 34-35 
D-16 Mark IV-D hydrophone, 
210-211 

HP hydrophone, 222 
HP laminated stack transducer, 
154-155 

HP-4 laminated stack, 154-155 
HU hydrophone, 223 
HU-9 hydrophone, 343 
JP hydrophone, 212-213 
JP sonar-listening equipment, 58 
JT sonar-listening equipment, 64 
NJ sonar-sounding projector, 66- 
69 

NL-124 hydrophone, 214-215 
NL-130 hydrophone, 216-217 
NM sonar-sounding projector, 
70-71 

NM-2 sonar-sounding projector, 
72-73 

NM-5 sonar-sounding projector, 
72-73 

NMA sonar-sounding projector, 
70-71 

NMB-1 sonar-sounding projector, 
74-75 

NMB-2 sonar-sounding projec- 
tors, 70-71 

NMC sonar-sounding projector, 
76-77 

NMC-1 sonar-sounding projec- 
tors, 78-79 

nondirectional, 320-321 
QCA sonar-ranging projector, 
90-91 

QCB sonar-ranging projector, 
90-91 

QCJ sonar-ranging projector, 
92-93 


QCJ-9 sonar-ranging projector, 
94-95 

QCL sonar-ranging projector, 96- 
97 

QCL-8 sonar-ranging projector, 
98-99 

QCQ sonar-ranging projector, 
108-109 

QCU sonar-ranging projector, 
114-115 

QGA sonar-ranging projector, 
116-119 

QGB sonar-ranging projector, 
120-121 

RCA hydrophone, 330-331 
SK 4610C projector, 158-159 
sword arm depth angle trans- 
ducer, 152-153 

TMSH No. 1 hydrophone, 343 
toroidal hydrophone, 205, 208, 
218-219, 347 

tubular hydrophone, 205, 220-221 
WCA-2 sonar-sounding projec- 
tor, 80-81 

WEA-1 sonar-ranging projector, 
132-133 

WEB sonar-sounding projector, 
80-81 

tubular hydrophone, 347 
Magnetostrictive Rochelle salt crys- 
tal transducers 

QCN sonar-ranging projector, 
100-102 

QCN-4 sonar-ranging projector, 
103-105 

QCO sonar-ranging projector, 
106-107 

QCS-1 sonar-ranging projector, 
110-113 

WCA-1 sonar-ranging projector, 
124-126 

WCA-2 sonar-ranging projector, 
127-129 

WEA-2 sonar-ranging projector, 
134-135 

Massachusetts Institute of Tech- 
nology (MIT), 208-209 
2VLF hydrophone, 343 
CMF condenser hydrophone, 42- 
43 


HK type hydrophone, 44-45 
HP hydrophone, 222 
HU hydrophone, 223 
HU-9 hydrophone, 343 
XMQ hydrophone, 347 
XMS hydrophone, 343, 347 


XMX hydrophone, 48-49 
XPA projector, 224-225 



Maximum range, scanning sonar, 
270 

MH transducers, 1, 2, 4, 22-23 
Mine detection, C49 hydrophone, 
306 

MIT 

see Massachusetts Institute of 
Technology (MIT) 

Moving coil hydrophone, pressure 
gradient 

lA hydrophone, 24-25 
2A hydrophone, 26-27 
Moving coil permanent magnet 
transducers 

T22 hydrophone, 202-203 
T37-T1 hydrophone, 202-203 
Moving coil projector, inertia con- 
trolled 

IK projector, 18-19 
4B projector, 14-15 

Naval Ordnance Laboratory, 194 
Naval Research Laboratory 
K-type hydrophone, 196-197 
OLA hydrophone, 46-47 
small object locator, 198 
SV velocity type hydrophone, 
200-201 

X-5 projector, 140-141 
X-6 projector, 142-143 
X-7 transducer, 347 
New London hydrophones, 204- 
208, 210-221 
NH4H2PO4 crystals 
see ADP crystals 
9A hydrophone, 318-319 
947 projector, 80-81 
94111A transducer, 345 
94120 transducer, 345 
94211A transducer, 345 
19-inch spherical magnetostriction 
type projector, 50 
NJ sonar-sounding projectors, 66- 
69 

NL124 hydrophone, 214-215 
NL130 hydrophone, 216-217 
NM sonar-sounding projector, 70- 
71 

NM-2 sonar-sounding projector, 72- 
73 

NM-5 sonar-sounding projector, 72- 
73 

NMA sonar-sounding projector, 70- 
71 

NMB-1 sonar-sounding projector, 
74-75 

NMB-2 sonar-sounding projector, 
70-71 

NMC sonar-sounding projectors, 
76-77 


INDEX 


359 


NMC-1 sonar-sounding projector, 
78-79 

N on-directional magnetostriction 

transducer, 320-321 

NRL 

see Naval Research Laboratory 

OAY sound meter hydrophone, 
282-283 

Oil exploration, use of tourmaline 
gauges, 241 

OLA hydrophone, 3, 4, 46-47 
lA pressure gradient hydrophone, 
1, 3-4, 24-25 
IJ projector, 343 
IK projector, 1, 2, 18-19 
100 in. QGA dome, 162, 166 

PAR sound level indicator hydro- 
phone, 209, 222 

Piezoelectric transducers, 226-239, 
275-276, 278-309 
Plan position indication (PPI) 

FM sonar, 261 
scanning sonar, 249 
XQHA sonar system, 250 
Practice attack meter, 316 
Pressure gradient transducers 
lA hydrophone, 24-25 
2A hydrophone, 26-27 
8A hydrophone, 316-317 
9A hydrophone, 318-319 
SV velocity type hydrophone, 
200-201 

Projector models 
see ADP crystal transducers; 
Magnetostriction trans- 
ducers ; Rochelle salt crys- 
tal transducers 

see also under names of indi- 
vidual models 
Projector standards, 1-3 

see also Standard transducers, 
USRL 

P-type hydrophone, 188-189 

QB type ADP projector 
BTL unit, 136-137 
Submarine Signal Co. unit, 146- 
147 

QBE-1, sonar-ranging projector, 
82-83 

QBE-2, -3 sonar-ranging projec- 
tor, 84-85 

QBF dome, 161-165, 170-171, 174- 
175 

QBF sonar-ranging projector, 86- 
87 

QBG sonar-ranging projector, 88- 
89 


QC sonar-ranging projector, 90-91 
QC spherical dome, 162, 165 
QCA sonar-ranging projector, 90- 
91 

QCB sonar-ranging projector, 90- 
91 

QCJ sonar-ranging projector, 92-93 
QCJ-2 sonar-ranging projector, 54, 
96-97 

QCJ-3, -4, -5, -6 sonar-ranging 
projector, 92-93 

QCJ-8 sonar-ranging projector, 96- 
97 

QCJ-9 sonar-ranging projector, 94- 
95 

QCL, -7 sonar-ranging projector, 
96-97 

QCL-8 sonar-ranging projector, 98- 
99 

QCN-1, -2, -3, sonar-ranging pro- 
jector, 100-102 

QCN-4 sonar-ranging projector, 
103-105 

QCO-3 sonar-ranging projector, 
106-107 

QCQ, -3 sonar-ranging projector, 
108-109 

QCR, -2 sonar-ranging projector, 
108-109 

QCS-1 sonar-ranging projector, 
110-113 

QCT-1 projector, 110 
QCU dome, 164 

QCU sonar-ranging projector, 114- 
115, 166-168 

QCU torpedo-shaped dome, 165 
QCU-1 dome, 122-125, 166, 167 
QCU-2 dome, 161-163 
directivity patterns, 167, 168 
transmission loss calibration 
chart, 163, 174 
QGA dome, 162-165, 172-174 
QGA sonar-ranging projectors, 54, 
116-119 

QGB sonar-ranging projectors, 120- 
121 

QGC projector, 350 
QJA dome, 53 

QJA sonar-ranging projector, 86-87 
QJB sonar-ranging projectors, 86- 
87, 122-123 
QL sonar 

see FM sonar 

Quartz crystal echo-ranging de- 
vice (USDAR), 332-336 
Quartz crystal transducer 
CIO transducer, 296-297 
low-frequency standard hydro- 
phone, 190-191 
type P hydrophone, 188-189 

gg)>TFIDENTIM7J^ 


Radio Corporation of America, 277 
2A condenser hydrophone, 326- 
' 327 

ADP crystal projector, 144-145, 
167 

electrodynamic hydrophone, 328- 
329 

magnetostriction hydrophone. 
330-331 

NMB-1 sonar-sounding projector, 
74-75 

NMC sonar-sounding projector, 
76-77 

QCL sonar-ranging projector, 96- 
97 

QGB sonar-ranging projector, 
120-121 

USDAR, 332-336 
WEA-1 sonar-ranging projector, 
132-133 

Radio sono buoy sound elements, 
208 

Receiving response of various 
hydrophones 

see name of individual hydro- 
phone model 

Response characteristics of various 
transducers 

see name of individual trans- 
ducer model 

Rochelle salt crystal transducers 
C37-5 hydrophone, 350 
S-124 hydrophone, 324 
SS-6 hydrophone, 325 

Rochelle salt crystal transducers, 
magnetostrictive 
see Magnetostrictive Rochelle 
salt crystal transducers 

Rochelle salt crystal transducers, 
X-cut 

5A hydrophone, 312-313 
5B hydrophone, 312-313 
5C hydrophone, 36-39 
7A hydrophone, 314-315 
AX-6 hydrophone, 304-305 
AX-6-F hydrophone, 304-305 
AX-47 hydrophone, 278-279 
AX-47-1 hydrophone, 278-279 
AX-50 hydrophone, 280-281 
AX-58A hydrophone, 282-283 
AX-79 hydrophone, 286-287 
AX-79-1 hydrophone, 286-287 
AX-83 hydrophone, 288-289 
AX-131 transducer, 294-295 
Cll-Al hydrophone, 40-41 
C13 transducer, 20-21 
C23 hydrophone, 298-299 
C37 hydrophone, 300-301 
C43 hydrophone, 302-303 

X./XI44 hydrophone, 304-305 


360 


INDEX 


C49 hydrophone, 306-307 
C50 hydrophone, 308-309 
Canadian NRE B1 hydrophone, 

192 

Canadian NRE FI hydrophone, 

193 

GA2 transducer, 234-235 
HK type hydrophone, 44-45 
JK sonar-listening equipment, 55 
JK-9 sonar-ranging projector, 
82-83 

JO parabolic hydrophone, 56-57 
JQ sonar-listening hydrophone, 
60-61 

MH transducer, 22-23 
QBE sonar-ranging projector, 82- 
83 

QBE-1 sonar-ranging projector, 
82-83 

QBE-2 sonar-ranging projector, 
84-85 

QBE-3 sonar-ranging projector, 
84-85 

QBG sonar-ranging projector, 
88-89 

underwater object locator, 338- 
340 

WCA-2 sonar-ranging projector, 
130-131 

XMX hydrophone, 48-49 
XPA projector, 224-225 
Rochelle salt crystal transducers, 
Y-cut 

2B projector, 10-11 
3B projector, 12-13 
5E hydrophone, 36-39 
6B projector, 16-17 
10 kc, 20 kc, and 40 kc trans- 
ceiver units, 322-323 
CY4 sample 3 A transducer, 228- 
229 

GD16-17 transducer, 236-237 
GD34Z-1 transducer, 238-239 
QBF sonar-ranging projector, 86- 
87 

Rochelle salt crystals 

dependability of X-cut, 1-2 
disadvantages of X-cut, 2, 3 
in Asdic transducers, 176 
in standard transducers, 2 
in USRL standards, 2, 3 
RQ51055 hydrophone, 282-283 

S-124 hydrophone, 324 
Scanning directivity pattern, 261 
Scanning sonar, 249-274 

bearing accuracy, 261, 270-271 
coverage rate, 272-273 
CR systems, 249-261 
directivity index, 254, 271 gj,, 


disadvantages, 249 
dynamic scanning directivity pat- 
tern, 261 

ER systems, 249-250, 261 
FM sonar, 261-270 
HUSL systems, 249-261 
maximum range, 271-272 
operational effectiveness, 270-274 
principles of operation, 249-250 
scanning directivity pattern, 261 
visual and aural recognition dif- 
ferentials, 271 
Search efficiency 
scanning sonar, 270 
searchlight sonar, 249 
Searchlight sonar, 249 
coverage rate, 273 
disadvantages, 249 
maximum range, 272 
operational effectiveness, 270-274 
7A hydrophone, 314-315 
733J transducer, 345 
733R transducer, 345 
Signal Corps General Development 
Laboratory, 194 

T22 and T37-T1 hydrophones, 
202-203 

6B projector, 1, 2, 16-17 
SK 4044 projector, 156-157 
SK 4610C projector, 158-159 
SK 5982 projector, 146-147 
Small object locator. Asdic, 184- 
185 

Small object locator, NRL, 198 
Sonar equipment, British and 
Canadian, 176-193 
Sonar equipment, U. S. Navy, 50- 
159 

code designations, 50-51 
echo-ranging equipment, 53-54, 
82-123 

echo-sounding equipment, 51-52, 
66-81 

experimental projectors, 54, 136- 
159 

frequencies, 50 

listening equipment, 51, 55-64 
ranging equipment, 54, 124-135 
Sounding equipment, acoustic, 51- 
52, 66-81 

Spherical projector, 19-in. mag- 
netostriction type, 50 
SS-6 hydrophone, 325 
Standard transducers, USRL, 1-49 
crystal properties for higher 
frequencies, 2-3 
hydrophone standards, 3-5 
low frequency standards, 2 
primary standards, 1 


ONFIDENTIA 


projector standards, 1, 2, 
secondary standards, 1 
Standard transducers, USRL, 
specific models 
lA hydrophone, 24-25 
IK projector, 18-19 
2A hydrophone, 26-27 
2B projector, 10-11 
3A hydrophone, 28-29 
3B projector, 12-13 
4B projector, 14-15 
5A projector, 6-7 
5C hydrophone, 36-39 
5E hydrophone, 36-39 
6B projector, 16-17 
AX-70 projector, 8-9 
AX-91 hydrophone, 30-31 
AX-124 projector, 8-9 
B19-B hydrophone, 32-33 
B19-H monitor hydrophone, 34-35 
Cll-Al hydrophone, 40-41 
C13 transducer, 20-21 
condenser hydrophone CMF, 42- 
43 

HK type hydrophone, 44-45 
MH transducers, 22-23 
OLA hydrophone, 46-47 
XMX hydrophone, 48-49 
Stanolind Oil & Gas Company 
tourmaline gauges, 246-248 
Submarine Signal Company, 276- 
277 

British type dome, 162 
NJ sonar-sounding projector, 66- 
69 

NM sonar-sounding projector, 70- 
71 

NM-2 sonar-sounding projector, 
72-73 

NM-5 sonar-sounding projector, 
72-73 

NMA sonar-sounding projector, 
70-71 

NMB-2 sonar-sounding projector, 
70-71 

NMC-1 sonar-sounding projector, 
78-79 

QB type projector SK 5982; 146- 
147 

QBE sonar-ranging projector, 
82-83 

QBE-1 (JK-9) sonar-ranging 
projector, 82-83 

QBE-2 sonar-ranging projector, 
84-85 

QBE-3 sonar-ranging projector, 
84-85 

QCA sonar-ranging projector, 
90-91 



INDEX 


361 


QCB sonar-ranging projector, 
90-91 

QCJ sonar-ranging projector, 92- 
93 

QCJ-9 sonar-ranging projector, 
94-95 

QCL-8 sonar-ranging projector, 
98-99 

QCN sonar-ranging projector, 
100-102 

QCN-4 sonar-ranging projector, 
103-105 

QCO sonar-ranging projector, 
106-107 

QCQ sonar-ranging projector, 
108-109 

QCS-1 sonar-ranging projector, 
110-113 

QCU sonar-ranging projector, 
114-115 

QGA sonar-ranging projector, 
116-119 

QGC projector, 350 

S-124 hydrophone, 324 

SK 4044 projector, 156-157 

SK 4610C projector, 158-159 

SS-6 hydrophone, 325 

WCA-1 sonar-ranging projector, 
124-126 

\VCA-2 sonar-ranging projector, 
127-131 

WCA-2 sonar-sounding projec- 
tor, 80-81 

WEA-2 sonar-ranging projector, 
134-135 

WEB sonar-sounding projector, 
80-81 

Submarine Signal Co. and RCA, 
JK sonar-listening equip- 
ment, 55 

Supersonic standard projectors, 
343, 344, 348 

SV velocity type hydrophone, 200- 
201 

Sweetwater underwater sound cali- 
bration station, 209 
Sword arm depth angle trans- 
ducers, 152-153 

T1 hydrophone, 244-245 
T22 hydrophone, 202-203 
T37-T1 hydrophone, 202-203 
10-kc transceiver unit, 322-323 
3A hydrophone, 3, 4, 28-29 
3B projector, 1, 2, 12-13 
Thuras-type hydrophones, 347 
TIH hydrophone, 347 
TMB tourmaline gauge, 242-243 
TMB-Tl hydrophone, 244-245 
TMSH hydrophone, 347 


Toroidal magnetostriction hydro- 
phones, 205, 208, 210-211, 
218-219 

Torpedo domes, 161 
Tourmaline crystal transducers 
HT-1 hydrophone, 186-187 ' 

K-type hydrophone, 196-197 
OLA hydrophone, 46-47 
Tourmaline gauges, 241-248 
impedance efficiency, 241 
requirements for measurement 
of explosive sounds, 241 
Tourmaline gauges, X-cut crystal 
Stanolind Oil and Gas Co. 

gauges, 246-248 
TMB gauge, 242-243 
TMB-Tl hydrophone, 244-245 
Transceiver units, 10, 20, and 40 
kc, 322-323 
Transducers 

see ADP crystal transducers; 
M agnetostrictive trans- 
ducers ; Rochelle salt crys- 
tal tranducers; Tourmaline 
crystal transducers 
see also under names of indi- 
vidual models, companies 
and laboratories 

Transmitting response of various 
transducers 

see name of individual trans- 
ducer model 

Tubular magnetostriction hydro- 
phones, 205, 220-221 
2A condenser hydrophone, 326-327 
2A moving coil hydrophone, 26-27 
2B projector, 1, 2, 10-11 
2 VLF crystal hydrophone, 343 
Type 135 Asdic set, 180-183 
Type 150 Asdic transducer, 184- 
185 

Type P hydrophone, 188-189 
UCDWR 

see University of California 
(UCDWR) 

Underwater object locator (UOL), 
338-340 

Underwater Sound Reference Lab- 
oratory (USRL) 

FM sonar system, 261-270 
scanning sonar, 249 
standard transducers, 1-49 
transducer designs, 226-239 
U. S. Naval Mine Warfare Test 
Station, 194 

U. S. Navy sonar equipment, 50- 
159 

University of California, 226-239 

^ ^oSnDENTfAlJn 


University of California 
(UCDWR) 

CJJ-78256 serial 20 sound head, 

‘ 226-227 

CY4 sample 3A transducer, 228- 
229 

EP2Z transducer, 230-231 
FE2Z transducer, 232-233 
GA2 transducer, 234-235 
GD16-17 transducer, 236-237 
GD34Z-1 transducer, 238-239 
UOL (underwater object locator), 
338-340 

USDAR (portable one-man echo- 
ranging device) 
calibration charts, 333-335 
system of operation, 332, 334 
U.S.S. SEMMES, 194 

WCA sonar projector, 124-131 
WCA-1 sonar-ranging projector, 
124-126 

WCA-2 sonar-ranging projectors, 
80-81, 127-129, 130-131 
WEA-1 dome, 161-163, 165, 168-170 
WEA-1 sonar-ranging projector, 
132-133, 175 
WEA-2 dome, 162 
WEA-2 sonar-ranging projector, 
134-135 

WEB sonar-ranging projectors, 80- 
81, 127-129 

WFA-1 sonar bottomside trans- 
ducer, 136-137 

WFA-1 sonar topside transducer, 
148-151 

X-5 projector, 140-141 
X-6 projector, 142-143 
X-7 projector, 347 
X-cut quartz crystal, CIO hydro- 
phone, 296-297 

X-cut Rochelle salt crystal trans- 
ducers 

see Rochelle salt crystal trans- 
ducers, X-cut 

XE 1-2 crystal hydrophone, 348 
XMQ hydrophone, 347 
XMS hydrophone, 343, 347 
XMX hydrophone, 4, 48-49, 344 
XPA projector, 224-225 
XQB-6S projector, 171 
XQHA CR scanning sonar, 250-254 
bearing accuracy, 261, 270-271 
calibration charts, 255-260 
coverage rate, 272-273 
description of system operation, 
250-254 


362 


INDEX 


directivity index, 254, 271 

dynamic scanning directivity pat- 
tern, 261 

operational effectiveness, 270-274 
projector efficiency, 254 


scanning directivity pattern, 261 see Rochelle salt crystal trans- 
visual and aural recognition ducers, Y-cut 

differential, 271 

Z-cut ADP crystal transducers 

Y-cut Rochelle salt crystal trans- see ADP crystal transducers, 

ducers Z-cut 


‘ONFIDENTIAL ? 















THIS ITfV contains S0«V!E ILLUSTRATIONS WHICH 
CANNOT BE RErCODl'CCO SUISfACTOnHY BY EITHCR 
THE ElECTfiOiT/rMC OR VHE PHOTG3TATIC PHOCESS. 











